do a /cat/proc/version, and look at the compiler version, redhat is know to use
a different compiler for kernel compiles than the installed system compiler.
if that's the case, compile the kernel on your own, or compile the driver with the
version you got from the command.
do a websearch for gcc 2.96 redhat and kgcc, even linus (who says almost nothing about
distributions) was, errm "not amused")