When I temporarily changed permissions of /var/log (not something I wanted to do), it got further but then failed trying to open the VT. The resulting log file was created by tc:staff.
I looked at your other post, and it seems like it could work. Although the file itself is suid, it does not currently run as root.
My present workaround is to run it from .xsession with "sudo /usr/local/bin/Xorg...". I'm not sure if this is a bad idea, but it seems to work. Xorg itself runs as root, and X apps run as tc.
Unfortunately one of the reasons why I wanted to get Xorg+nvidia running is so I could play Unreal Tournament in TC (more ram available than in Debian), but apparently it is not compatible with something in TC...I messed around with it for a long time and couldn't get it going at more than about 0.05 fps. UT2004 seems to be compatible, but my machine is not powerful enough to enjoy it.
But on the plus side, MPlayer will run fullscreen, Blender runs much more smoothly , and hopefully I'll be able to get my wacom working in TC one of these days.