Question SOLVED: logged-in users get Fatal error & cannot edit category titles

Hi
This is a strange error that has me stumped. I cant think of anything Ive changed on the site recently, but there must be something.

Heres the error that logged in users get when trying to browse the forum.

Fatal error: Call to undefined method stdClass::_getFieldType() in /home/ (mysite) /public_html/includes/database.php on line 664

There is also different error - prior to me discovering the above, I was working on a problem where I can not edit or add a category without the name of that category changing to a number 0. I could add proper titles by editing via phpmyadmin, but saving in J backend always sent the title back to 0.

I bet these two problems are related.

Im working with the latest Fireboard on Joomla 1.0.15
Non-logged in users can browse the forum no probs.

I just installed Kunena & same behaviour.

Thanks for reading.

How about some more info?

Joomla version. Server config? Recently installed extensions? These things don't just happen by themselves.

It's OK, I found the culprit - it was QueryCache. I uninstalled that & all OK again, & can edit categories & browse forum as logged-in.

Query cache does not work with legacy. It's known issue and found in QueryCache documentation.

I was using qcache-1.0.0rc2.zip which is for Joomla 1.0 series.
I didn't know it had documentation ... there's the faq, which is interesting. My Page Cache was using the File method to save....Do you think QueryCache should work OK with Fireboard on a 1.0.x installation?

Honestly I don't know.