The issue is caused by the Admin pack’s entityEditProducts.aspx included JQuery conflicting with an include in a customized skin. The JQuery is for the ProductCSVHelpers on 'Options' tab.
If you run into this issue, the easiest workaround is to do as others suggested, and just disable the CSVHelpers by either removing them or set the visibility of each control to false. Remove the line ' <script type="text/javascript" src="scripts/jquery-1.4.4.min.js"></script> ' and edit products will work as well.
It is NOT suggested to roll-back the admin service pack, as it does still include updates and bug fixes as well.
Erik Sutton
AspDotNetStorefront Technical Support