On the left it says "Run Install Script" and there are no other menu items. So it looks like you still need to run the install script. Thanks for reporting this error though. If there wasn't this error, there would have been a page telling you to run the install script.
If this still happens when clicking that link, let me know. This error is new since 4.0.8 Patch Level 1. It looks like the patch asks extra code to run that isn't available before the add-on is done installing.