Amnesia won't launch

10.6.7, 2.2 GHz C2D, GeForce 8600M GT

The (non-Steam) demo worked fine, but trying to launch the full version from Steam bounces the game's Launcher.app in the dock for a while then fails. Then it repeats that until I force-quit Steam. This still happens after removing and reinstalling Steam and Amnesia, including all of ~/Library/Application Support/Steam.

system.log has the following:

Apr  8 19:39:38 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Steam error:  SteamGetAppCacheSize(80751,0x14df7fe0,0xbfffa0b0) failed with error 1: cache path contains invalid characters
Apr  8 19:40:54 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to create Service pipe
Apr  8 19:40:54 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to connect to Steam Service
Apr  8 19:40:54 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to load Steam Service
Apr  8 19:40:54 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: ServiceStart: failed to start
Apr  8 19:42:18 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to create Service pipe
Apr  8 19:42:18 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to connect to Steam Service
Apr  8 19:42:18 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to load Steam Service
Apr  8 19:42:18 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: ServiceStart: failed to start
Apr  8 19:42:18 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Game update: AppID 57300 "Amnesia: The Dark Descent", ProcID 16448, IP 0.0.0.0:0
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/1bb042c0 [GameOverlay_InputEventStream_16470_avail.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/1bb042c0.2 [GameOverlay_InputEventStream_16470_avail.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/1d7d2671 [GameOverlay_InputEventStream_16470_written.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/1d7d2671.2 [GameOverlay_InputEventStream_16470_written.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/247cd839 [GameOverlay_GameExitingEvent_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/247cd839.2 [GameOverlay_GameExitingEvent_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/2c76592a [SteamOverlayRunning_57300.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/2c76592a.2 [SteamOverlayRunning_57300.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/2f301147 [GameOverlay_ScreenshotStream_16470_avail.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/2f301147.2 [GameOverlay_ScreenshotStream_16470_avail.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/9bdd1c33 [GameOverlay_ScreenshotStream_16470_written.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/9bdd1c33.2 [GameOverlay_ScreenshotStream_16470_written.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/a9605c8d [GameOverlay_InGameRenderingCompleted_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/a9605c8d.2 [GameOverlay_InGameRenderingCompleted_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/ad40440b [GameOverlay_VGUIPaintingCompleted_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/ad40440b.2 [GameOverlay_VGUIPaintingCompleted_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/c519bad4 [GameOverlay_SerializedWorkQueued_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/c519bad4.2 [GameOverlay_SerializedWorkQueued_16470.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/caa1b07 [GameOverlayRender_PaintCmdStream_16470_written.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/caa1b07.2 [GameOverlayRender_PaintCmdStream_16470_written.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/fb397160 [GameOverlayRender_PaintCmdStream_16470_avail.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /BSem/fb397160.2 [GameOverlayRender_PaintCmdStream_16470_avail.BinSemLock]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/2d4274e2 [GameOverlay_ScreenshotStream_16470_avail]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/5e95fb96 [GameOverlay_GameExitingEvent_16470]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/64fdc905 [GameOverlayRender_PaintCmdStream_16470_avail]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/733ff647 [GameOverlayRender_PaintCmdStream_16470_written]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/88799783 [SteamOverlayRunning_57300]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/97333987 [GameOverlay_SerializedWorkQueued_16470]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/a03bdfc7 [GameOverlay_InputEventStream_16470_written]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/b4035323 [GameOverlay_InputEventStream_16470_avail]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/c5e594ff [GameOverlay_VGUIPaintingCompleted_16470]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/d7d015e2 [GameOverlay_ScreenshotStream_16470_written]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Evt/de6e8e5f [GameOverlay_InGameRenderingCompleted_16470]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /MTX/1f3a7100 [GameOverlayRender_PaintCmdStream_16470_mutex]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /MTX/1f3a7100.2 [GameOverlayRender_PaintCmdStream_16470_mutex]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /MTX/5685cce7 [GameOverlay_ScreenshotStream_16470_mutex]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /MTX/5685cce7.2 [GameOverlay_ScreenshotStream_16470_mutex]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /MTX/cfc4eb26 [GameOverlay_InputEventStream_16470_mutex]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /MTX/cfc4eb26.2 [GameOverlay_InputEventStream_16470_mutex]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Shm/40c46331 [GameOverlay_ScreenshotStream_16470_mem]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Shm/6ccd6d91 [GameOverlayRender_PaintCmdStream_16470_mem]
Apr  8 19:43:34 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16470 from: /Shm/84892b96 [GameOverlay_InputEventStream_16470_mem]
Apr  8 19:43:34 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: ExecSteamURL: "steam://run/57300"
Apr  8 19:43:34 hostname com.apple.launchd.peruser.501[177] ([0x0-0x234234].com.frictionalgames.AmnesiaSteamLauncher[16448]): Exited with exit code: 255
Apr  8 19:44:49 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to create Service pipe
Apr  8 19:44:49 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to connect to Steam Service
Apr  8 19:44:49 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Failed to load Steam Service
Apr  8 19:44:49 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: ServiceStart: failed to start
Apr  8 19:44:49 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Game removed: AppID 57300 "Amnesia: The Dark Descent", ProcID 16448 
Apr  8 19:44:50 hostname [0x0-0x212212].com.valvesoftware.steam[14057]: Game update: AppID 57300 "Amnesia: The Dark Descent", ProcID 16487, IP 0.0.0.0:0
Apr  8 19:44:50 hostname com.valvesoftware.steam.ipctool[14101]: [Cleanse]: Removing pid: 16448 from: /BSem/12a646bd [GameOverlay_InGameRenderingCompleted_16448.BinSemLock]

(etc...)

Okay, so where do I go for tech support if not here?

Torchlight exits with exit code 1 and pops up a window: "Fatal Error. Steam must be running to play this game (SteamAPI_Init() failed)."

So where the ♥♥♥♥ do I go for tech support if no one's monitoring this forum? Don't say Frictional, because they say it's a Valve problem.

[SyntaxError]

http://support.steampowered.com/