Did a complete uninstall and reinstall of GK 0.28.8. Ran through setup according to the guide for XviD. Got the same error message when I tried to do the Compressibility Check. Deleted the xvid first/second pass setting files. Reconfigured first and second pass. Tried again. Same result. I've used GK on plenty of other DVDs. Could it be this particular DVD? I'll go back and try it on an old one.