so00
Silly question... but you didn't mention it. You did run the altertable5.5-6.0.php script when you upgraded right?
What happens when you go under admin and click "approve new users". Does anyone come up under there as unapproved?
<img border="0" title="" alt="[Smile]" src="images/icons/smile.gif" />
"Happiness comes through doors you didn't even know you left open. "
