$SUBJECT/mri/T1/COR.-info

and look for the line starting with 'fov'. The number following it should be 0.256, not 0. If it was 0, that is the problem, and you can just change the value to 0.256, save the file, and load tksurfer again.

If not, it could be graphics problem; try updating your graphics drivers or try the statically linked version (see the FAQ items having to do with tksurfer failing to start up).
2003-Jul-07 10:33am kteich, kteich