[PyMOL] Can't PNG a morph

[Brian Houck-Loomis]

Hello,

I've made a simple morph between two conformations using rigimol.  I  
can load the resulting refined morph PDB and I can set a movie.sweep  
just fine.  The movie plays well and all looks good.  The problem  
arises when I try to export the movie in either QT format (vi  
MacPyMol) or in iPymol using the mpng command.  All the images are  
blank (just a black screen).  Any suggestions?

Thanks,
Brian