Ok the last thing I did was install a Support Tickets plugin (I think it was something like wpsc Support Tickets or something similar) and now when I try to access my dashboard (as the super admin) on any of my sites (in my multisite) I get the "You do not have sufficient permissions to access this page." screen. This is as soon as I log in I get taken to this screen, and I can't access my dashboard at all. Grrrrrrr.
How can I access my dashboard and deactivate this plugin now?