DB tuner breaks after going to Views 3

I can't reproduce this yet, but may have time later today.
What I did:
Installed dbtuner on a test site. Used it to convert to innodb. Set a few other parameters I unfortunately can't remember.
Everything seemed fine.
Upgraded Views to 6x3.0
Now, when I try to go to /admin/settings/dbtuner I get
HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.
Disabled db tuner and thought I'd uninstall and reinstall. Doesn't seem to be an uninstall mechanism.

But I have a backup of even the test db, so.... more info later perhaps.