Custom Drupal Zen Theme gets deactivated

I’ve created a custom theme starting from Zen and used it for a Drupal 6.x site, hosted on Dreamhost. However, for some reason it gets deactivated (even though it stays set to the default theme). When I log in I can activate it again, but soon enough it gets disabled again.

Any hints on what could be going wrong?

Or should I force this theme somewhere in the DB or in the settings.ini? I think I can only set the default over there but not enable it.

Site is still in progress, but doubting to keep it hosted here, because of Drupal slowness.

— stefkeB —