Hi Greg,

Thanks- I'll send you the directory offline.

>Is there anything in your Registration directory? Perhaps it is failing at an earlier stage.

Yes, the registration directory looks fully populated- has subdirectories for affine (and warp when I select it), subdirectories for each of the floating image stacks, and each of those subdirectories has files "cmd.sh", "registration", "settings", "statistics", and "studylist".  Also, the "registration" file seems to have actual transformation values that go beyond an initial value.