Did you guys see this post?
http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/42/threadid/134732/scope/posts/threadpage/2/Default.aspx
I just installed DNN 4.7 and the latest Media Module 3.02.03 and am having the same problems. In the event log it appears that whenever the EventQueue throws that error the application shuts down and restarts. That would explain the long page loads. The whole DNN app has to reload every minute or two. Very annoying!
I went into the EventQueue table and found the offending entry for the media module and set its IsComplete value from False to True as was recommended in the above referenced post. We'll see how it goes. I wonder if the reason the error persists even after you've un-installed the Media Module is because that entry is still in the EventQueue table? Checking to see if it's still there after un-install and removing it if it is may resolve the issue.
Crossing my fingers.
Matt