Just installed zenphoto and everything seems to be OK . (running on OS X Server 10.4.10)
Only problem is when I use a theme other than Zenphoto Default.
If I choose any other theme from the Options part of the admin section... when I then view the gallery, it seems stripped of any CSS styling, and when I actually click on an album I get this error:

`Not Found

The requested URL /xdesigner/zenphoto/< was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

`

When I switch back to the default theme all the problems goes away.

I'd like to use other themes! Any clues?

Maybe a problem in your .htaccess, with the RewriteBase argument unset.
Have you any problems using the admin interface ? Like 404 errors while trying to get a page..?

Not really sure what I'm doing, but I think I've managed to solve the problem by changing
`

?=

to

?php echo

`

in all the php files in the theme. Something to do with the PHP5 I installed I think. There's probably an easier way (like allowing PHP 5 to recognise "?=" properly)