The OP also mailed me personally about this issue.
He used an iPhoto selection. Because he used different selections with the same template successfully before, I thought that the problem could possibly be with one of he photos in the selection. But before we could figure out where the problem originated, he sent the photos to another computer with Galerie installed. After an initial error about the template and choosing a different template, it worked fine there.
So, no definite answer about what the problem was.