Map problems...

[Korpze]

Every time I try to run a map, it gives me the error LoadPortals: couldn't read c:\program files\steam\steamapps\common\alien swarm\sdk_content\mapsrc\[map name].prt
Well, the BSP is written in the mapsrc folder, so I copied it into the Maps folder in the Swarm folder, run the game and the game instantly closes when I try to run the map.

[mr.ioes]

Maybe the FAQ can help you (http://forums.steampowered.com/forums/showthread.php?t=1378963).

This is the most common question asked here and therefore there are already tons of other threads with the same(?) problem here!