This is pretty puzzling. We aren't setting any limitations going into that dialog window. It's managed by QuickTime, and we supply a movie for it to work with. If you try with another file are all of the other resolutions available?
If this is only happening with one file, we would like to take a look at two things: your current Podner preferences file, which should help us duplicate the issue here, and the movie file that it's occurring with.
If this happens with all files, we would still like to see your Podner preferences file so we can test with it here.
The preferences file is located at /Users/[your username here]/Library/Preferences/com.splasm.podner.plist.
If sending the file is necessary and it's fairly large, you could use
http://www.yousendit.com for free. Please address the file to
support@splasm.com.
Thanks Craig.