compiling application with prof results in undefined references

[Niels van der Velden]

Hi all,
I have an application that uses a package called 'uust'. 
Normally I would compile using;

ghc -O2 -o genAST -fglasgow-exts -package uust GenAst.hs

This works fine. However, I want to profile my application and therefore need
to add -prof. The uust package was compiled for profiling (there are _p files),
but when I compile using;

ghc -prof -O2 -o genAST -fglasgow-exts -package uust GenAst.hs

I get undefined references during the link phase;

GenAST.o(.rodata+0xe5f0): undefined reference to
`UUziParsingziInterface_lvl8_closure'
GenAST.o(.rodata+0xe630): undefined reference to
`UUziParsingziInterface_zdwevalStepsIOzq_closure'
GenAST.o(.rodata+0xe6cc): undefined reference to
`UUziPrettyziBasic_lvl19_closure'
GenAST.o(.rodata+0xe6e8): undefined reference to
`UUziParsingziInterface_lvl8_closure'
GenAST.o(.rodata+0xe724): undefined reference to
`UUziParsingziInterface_zdwevalStepsIOzq_closure'

and many many more. I'm kinda in the dark here what I'm doing wrong.
Can anyone help?

regards, Niels

PS I'm using ghc-6.4 (and have ghc-prof of course).