First off I'm locked out, then after disabling the main php file I get a message saying the Admin Tools install is corrupt and to reinstall it twice, without deinstalling.
Tried this - makes no difference, I just get locked out again, and the same corrupt message.
This is also happening with another site of mine on the same host but a different server (UK2net) and in a different Joomla install (2.5.27).
To be honest, I think this would happen on all my sites if I upgraded Admin Tools Pro from 3.1.1 to 3.3.1., as I'm not getting this problem in any site with Admin Tools 3.1.1 installed, but it is happening to every site I've upgraded to 3.3.1.