[microleo]

Originally Posted by Dragokas hi, microleo! Did you compile an extension directly from VS?

check your vs options:
1. Debug-left 4 dead 2 / Release-left 4 dead2
2. check Project Property (C/C++)->(General)->(Include Directories):
..;
..\sdk;
$(SOURCEMOD)\public;
$(MMSOURCE)\core;
$(MMSOURCE)\core\sourcehook;
$(SOURCEPAWN)\include;
$(AMTL);
$(AMTL)\amtl;
$(HL2SDKL4D2)\public;
$(HL2SDKL4D2)\public\engine;
$(HL2SDKL4D2)\public\game\server;
$(HL2SDKL4D2)\public\tier0;
$(HL2SDKL4D2)\public\tier1;

3.make sure that sdk are installed