Dear Freesurfers: When I display and edit surfaces with tksurfer, the image can be loaded correctly, but whenever i rotate it, load curvatures, or load patches, it always freezes after my first operation and can't continue with the next operations. The freesurfer version i use is FS 4.5.0 under Fedora core 12, and the woking momory of computer is 4 Gigabytes with 4 processors, also enough hard disk space is available. can someone tell my what the problem is, and how i can fix it? thank you very much! changming