I don't know. I turned off the code here:
`// If mod_rewrite is true above, zenphoto's image page URL's usually end in .jpg,
// set this if you want something else appended to the end (helps search engines).
// Examples: .html, .php, /view, etc.
// $conf['mod_rewrite_image_suffix'] = '.php';`
And completely dumped and resetup the thinkdreams.com/zenphoto DB, and now it works again.
But I'll submit a bug to the tracker anyway.