"Duplicate entry" error on admin login

[benbroad]

Hi, I have a root server II from 1and1 that we have only just started using. I have done nothing other than enter my user data, change the admin password, and grab updates for the core apps (smtp, pop3, apache).

Now when I try to log in I get the following error:

Unable to query database: Duplicate entry '52-Contact Name' for key 1
0: /usr/local/psa/admin/plib/class.ActionLog.php:663 psaerror(string "Unable to query database: Duplicate entry '52-Contact Name' for key 1")

It's Plesk 7.5.4 running on FC3 on a decent hardware setup.

Any idea which table might be causing the problem?

Kind regards,
Ben the geek.