Cesar,

> Has anybody successfully built an FLL that uses Microsoft Foundation Classes. I get a lot of link conficts with the WINAPIMS.LIB.

Adding MFC support to project requires including CWinApp derived class, which conflicts with winapims.lib (_DllMain is already defined here). I don't know any workaround, so my suggection is to use STL, ATL7 (in VC++.NET) or WTL instead of MFC, if it possible. STL includes such classes as strings and containers. ATL7 and WTL also include strings and many simple classes like arrays. WTL additionally contains large set of windows classes similar to MFC.
FLLs are now considered as outdated technology with many disadvantages. IMO developing of external libraries as FLL may be appropriate only in rare cases, such as UDF for SQL queries. Instead of FLL you could create this library as ATL COM library or as MFC OCX. If FoxAPI is not used in your project, then you can create also standard MFC DLL.

> If that is not possible, would it be possible to create an Microsoft Foundation Classes DLL and call it from inside the FLL?

Yes, you can call standard MFC DLL (not a MFC extension DLL) from inside the FLL.