Since several users have submitted bugs related to missing files in the admin section I just released a new version of Gregarius, which should correct this problem.
You can download Gregarius 0.3.6 here.
The problem was triggered when apache was lacking the mod_rewrite module, which would prevent accessing the admin section.
Changelog:
Fixed a bug that would prevent accessing the admin section when mod_rewrite is not enabled
Fixed a bug which would prevent non-english language packs to work in the admin section.
Added item pruning to the admin section, which allows you to delete items older than a given period.
After reading this [german, babelfish] blog entry I added item pruning to the admin section, which allows you to delete items older than a given period of time to save disk- and database space.
Update from CVS if you wanna give it a try, or wait for the next file release, which should follow in a couple weeks.