Minimum Requirements:
* Windows 98, ME, 2000 or XP, Mac OS X 10.2.6, Linux, FreeBSD or Solaris
* GeForce 2 or higher 3D graphics card
* 1 Ghz CPU
* 512 MB RAM
* 1 GB free disk space
* 56k modem Internet connection
Your problem might be related with your graphics card. See if it meets the minimum, and if positive, try downloading newer drivers.
If you haven't used your char since the update, perhaps it was left in a zone that is no longer a valid one, and start falling over and over again. If that's your case, when you manage to log in again, try using /die command, that will teleport your char to the start of the DR map.
But first, try to solve that graphical issue. Also, sometimes a screenshot might be of use, to know what you're exactly describing, just for future reference