Very hard to say. It could be a bug in perl. It could be a bug in Inline::C. It could be a bug in your C code. It could be a bug in your C library. It could be a bug in your compiler. It could be a bug in the compiler used at ActiveState. It could be a bug in whatever SMS code you are linking with.

Even if you show us the code, it'll be almost impossible to tell. You'd need the code and a stacktrace from a debugger for starters. And someone with time.

Abigail