| The problem comes when we try to render the results from this
| analysis.  We consistently get:
| >> ??? Bad magic number in image handle.
| Error in ==> /usr/local/spm99b/spm_slice_vol.mexaxp
| Error in ==> /usr/people4/richard/matlab/spm_render.m
| On line 159  ==>                        X   = spm_slice_vol(X0,spm_matrix([0 0 
| and I can not figure out what's different between this rendering
| and other PET analyses which we've rendered.  The obvious thing is
| the presence of an explicit mask but I don't understand why this
| would prevent us from rendering our results.  Can anyone shed some 
| light on this?

I can't fully figure this one out.  The error message occurs because
spm_slice_vol is trying to resample a 12 x something matrix (because
the mex files still support the old handles that spm_map_vol used to
generate).  I'm guessing that one of the dimensions of your results
is 12 voxels.

I guess I'd better drop supporting the old-style volume handles now.