Comment 4 for bug 666175

that '_' is a #define normally replaced at compile time; that the compiler is actually trying to match it as some valid token shows that the file that #defines '_', DCPlusPlus.h, has not been included.
this is most likely a case of including stdinc.h but not DCPlusPlus.h; i suggest you modify your precompiled headers to include both stdinc.h & DCPlusPlus.h (see the top of win32/stdafx.h).