INTERNAL COMPILER ERROR vc7.1

I was porting some code from vc6 to vc7.1 and I got stuck in:

 

c:\build\main\.......\inc.h(27) : fatal error C1001: INTERNAL COMPILER ERROR

(compiler file 'msc1.cpp', line 2701)

Please choose the Technical Support command on the Visual C++

Help menu, or open the Technical Support help file for more information

 

Looking trough newsgroups microsoft.public.dotnet.languages.vc gave me a good hint:

"I spoke with Microsoft incident support for my MSDN licence and the fix is:

#if _MFC_VER < 0x0700
class CString;
#endif

CString is not a class in MFC anymore. It is a template in ATL so forward
declarations are invalid."

So I searched for CString forward declarations and I solved - quickly - my problem.