Try re-uploading all files & folders – except the wp-content folder – from a fresh download of WordPress.
That looks like an issue with your DB Cache plugin – the fix is to delete the plugin (which hasn’t been maintained in some time anyway). More details here: http://www.techbeast.net/2012/06/13/wordpress-3-4-fatal-error-upgrading-database/
Just tried this. Still getting this error.
I tried esmi’s approach, that is… not Amy’s idea, yet. I’ll try that now.
That’s now been confirmed as a fix for this specific error, so it should work. We’re still actively collating these kinds of fixes. 🙂
The info at Amy’s link worked. Big Thanks!
Follow-up: DB Cache Reloaded Fix has been updated and it seems to work fine now.
