Well, Linux 2.6.18-92.1.22.el5 is the name of the kernel, not of the distribution. But from the "el5" piece at the end I'm going to guess it's Red Had Enterprise Linux v5.
As to FORTRAN versions. Type
in the terminal. Does it return information on the program version or says there's no such command found?
I think you need to install the gcc package. I'm not familiar with RHEL, so I'll leave it to somebody else to tell you the exact procedure.