relocation error

relocation error: ... undefined symbol : Every time I startup my app I get this error. The largest part of my app is coded in a shared library (I''m doing this in linux btw), everything compiles without problems. I''m compiling with the -fPIC flag so my code should be position independent. I''ve worked with shared libraries before and never experienced any problems (that was in C, this library now is in C++, but I don''t think that could cause the error). The undefined symbol is part of the library, so the symbol exist''s. Anybody got an idea how I can solve this or what''s causing it ?