Deleting MarketPress and CustomPress

I recently installed a premium plugin called "Open Beacon Video Comments" that caused a conflict with a few WPMU Dev plugins (MarketPress, Classifieds, and CustomPress. As video commenting will be a major part of my site, I'd like to set up the Open Beacon plugin first and then go back and try to resolve the conflicts later.
So, I managed to Network Deactivate the offending plugins except for CustomPress.
I'm getting an error message at the top of my Dashboard that says:

nversion in /home/lyrixtube/public_html/wp-content/plugins/directory/core/custompress/core/core.php on line 81

And although I deactivated and then deleted it, it's still showing up in the left sidebar as an active plugin.
I'll need to set up CustomPress and MarketPress eventually, so I'll have to figure out why it's doing this. Can someone please please help me resolve the conflicts?
Thanks so much!