Hi,this is about segmentation fault.I have a cpp program that works really well in windows but ,fails in unix?

i have a perfectly working program..but it works only in windows(done with visual studio 6,c++).when i put it in unix platform and run i get segmentation fault.this prog. is to convert regular expressions to nfa.it has a stack.the segmentation fault occurs only when i have pushed '*'.And about the unix platform...we have a seperate unix server residing at our college computer centre..everyone has been given an account to access it (must have fixed memory allocation for each person).it is in this server i tried to run my program.check this out........