Recommended method to submit Mathematica in graphical mode:
ssh yourusername@beo03.unifr.ch
qrsh -pe smp 8 xterm
8- means number of cpus. If you need 1 cpu put there 1 or skip (-pe smp 8) but only for 1cpu jobs.
/apps/bin/mathematica
You can also use batch mode submittion with script.
In your .bashrc you should have PAHT to executables
export PATH=/apps/mathematica/7.0/Executables:$PATH