Segmantation fault

I was running MODELLER on Atlhon with Mandrake 7.02. The benchmarks runs well, but when i try modelling my protein the program returns the following message: /usr/local/bin/modeller4/bin/mod4: line 39: 2793 Segmentation fault /usr/local/bin/modeller4/bin/${EXECUTABLE} $STEERF >$LOGF Whats wrong???

Thanks in advance

Hmuniz.