Attempted to create unknown entity

[zombie@computer]

still sounds like it doesnt compile right, or at least does not load the dll's you compiled. Try adding code in some existing weapon and see if that runs.

[Zombie Killa]

I see one problem

class CWeaponColt1911 : public CHL2MPMachineGun
{
public:
DECLARE_CLASS( CWeaponColt1911, CHL2MPMachineGun );

should be

class CWeaponColt1911 : public CBaseHLCombatWeapon
{
public:
DECLARE_CLASS( CWeaponColt1911, CBaseHLCombatWeapon );

That need's to be matched with the one in the stubs file.

[Codexofwisdom]

I notice that tutorial is missing the "add the gun to your sdk_shareddefs" files step (it seems every weapon tutorial misses one step or another). Did you do this?
There should be a tutorial in the docs folder of your mod that will walk you through this, as well.

[ProZak]

Is your mod based on singleplayer or Half-Life 2 Deathmatch?