[TYPO3] Can't log in to BE (MySQL 5.1 error)

[Lamb, Brian]

I wanted to send this message once more before I open a bug report:

 

Last week I was running MySQL 5.0 with Typo3 4.2 and all was working
fine. However, I upgraded MySQL to version 5.1 and now the login
functionality is broken. Login is handled through LDAP but even the
admin password (not LDAP) does not work. However, the website still
displays the content so it is pulling information from the database but
I don't understand why the login is broken.