CallDLL is for calling your own functions in your own dll, as the docs state the function prototype at the other end has to be in the form:
Update your Blitz3D and use the new decls system if you want to call standard windows dll's and the like.
extern "C"{ _declspec(dllexport) int _cdecl my_dll_func( const void *in,int in_size,void *out,int out_sz ); }
Update your Blitz3D and use the new decls system if you want to call standard windows dll's and the like.