What was the last extension you have installed before Universal Email?
And as a test, you can just rename your configuration folder, which will remove your extension and then install UE by itself and see if you get the error. You can always rename the configuration folder back to get your extensions back. I just want to see if renaming your configuration folder does resolve the issue.
Another question, did UE ever worked for you, or did it always have this issue?
Please post back with the results.
