[eluser]TheFuzzy0ne[/eluser]
I think this might be an issue with your host. They probably aren't running the latest stable version of MySQL.
There's a bug report [url="http://bugs.mysql.com/bug.php?id=27967"]here[/url], but it suggests that the problem has something to do with transactions, which the sessions class does not use.
Are you using InnoDB and not MyISAM? If so, I'd suggest using MyISAM instead.