The problem is a bug in SGI's X11 server that only show up on some systems -- the server reports that it supports the "double buffer extension" (DBE), but in fact does not. AFNI detects the support for DBE, but when it tries to use it to draw the outlier graph, you get the error message. The solution is to set the environment variable AFNI_NO_XDBE to YES -- see [
afni.nimh.nih.gov] if you need help on setting such variables.
bob cox