"Undefined reference" during installation
===

I'm trying to install some scientific software (specifically the visualization tools xvs and DV), but I keep getting messages of the form

undefined reference to `_gfortran_----_----'

or in another case

/usr/lib/gcc/i686-redhat-linux/4.4.6/../../../libforms.so: undefined reference to `X----'

which eventually lead to errors. I'm very computer illiterate so I have very little understanding of what's happening here and how I can fix it. During configuration it seems to have no trouble locating the Fortran compiler and xforms library (which seem to be implicated here). I'm sure I have gcc-gfortran, libgfortran, xforms, and xforms-devel installed. What might be causing this?

Thanks!