I need help downgrading.

[fiercefox]

Hey, I need help downgrading ,I recently upgraded to 1.5.12 and I don't like it, and I'd like to downgrade back to 1.4.27, and I tried doing it manually and everything worked, but when i click on thumbnails it says

"Critical error
There was an error while processing a database query"

Can someone PLEASE help me or make a tutorial for me?

[Nibbler]

Downgrading is not supported. The only way to go back is to restore a backup made prior to updating.

[fiercefox]

So, if when I upgraded and I had a backup, it would work??

[Joe Carver]

The docs explain it well:
http://documentation.coppermine-gallery.net/en/upgrading.htm#downgrading