I'm guessing you did NOT successfully upgrade to MySQL5
My phpMyAdmin shows MySQL client as 4.1.18 with MySQL server 5.0.18
There was some silliness with rpm versions, I'm going to build an RC3 system next week & I'll update the MySQL5 how to that's in this forum with the suggestions posted after I've tested it.
Meanwhile, I'd check that you did get the mysqlclient rpm to load, and read the how to very carefully, the first methods kill data but do remove the old MySQL files .