[Haskell-beginners] ghci and module with FFI code

Hey, I wrote a little package which gives bindings to a C++ library (to the random forest from vigra). Works fine! But when I try to load a module using it in ghci, and run an function (which is unrelated to the FFI bindings) I get: /lib/hsVigraRF-0.1.0.0/ghc-7.6.2/HShsVigraRF-0.1.0.0.o: unknown symbol `_ZGVZN5vigra10rf_defaultEvE6result' _ZGVZN5vigra10rf_defaultEvE6result is a symbol from vigra. So why do I get this in ghci and not when compiling/running? What can I do about this? Thanks! Nathan