You don't specify what operating system you are using. I'm using a Mac, and the export to PSD works fine. Perhaps you should try downloading the latest build of the program. If that doesn't work, LumaPix has some forums and contact pages.
using windows 7, latest build. Just purchased, downloaded today. I did submit a request in the forums. I noticed other folks having similar problems. It doesn't happen on every collage. This is something they should have mentioned up front if they have limitations on certain collage types.
Ended up getting a refund. Too many bugs when with updating websites and exporting as PSD files. Also, many templates have locked elements and they cannot be unlocked by the user.
I guess I'm going to stick with indesign or maybe re-purchase the cheaper version if I just want to export jpgs...
