I think that's not too surprising; remote OpenGL with X11 doesn't work terribly well usually, and we don't recommend it for suma. The afni GUI is usually fine with a reasonable connection because it doesn't have the openGL requirement. You might try an alternative solution like VNC. Just through what I could find in a google search for that error, others have recommended removing local nVidia drivers in order to have more generic openGL drivers on the local system. I can't say how much difficulty that might be, so I hesitate to recommend that solution.
