Same problem in v1.2.4 as in previous version v1.2.3, reported in:
http://www.zenphoto.org/support/topic.php?id=4926
The only way I'm overcoming it is the one I reported in mentioned topic.
Are you sure you updated everything incl. the theme correctly? I don't see that in the default theme.
I'm using StopDesign and I've overwritten all 1.2.3 theme files with new 1.2.4. Should I try a new theme files (1.2.4) upload?
Worth a try.