If you are having problems running X applications (or GUI driven, java, etc.) remotely then most likely you need to use the -Y option instead of the -X/-x (i.e. ssh -Yl lab2-4.eng.utah.edu)
This is caused by a new change in any Openssh version newer than 3.7.1
For more information, including other options for running graphical applications consult the SSH or Remote Access FAQ pages.
Posted in: Remote Access, SSH Related, Unix