Looks like Adobe changed it's support website again... try this:
- Go to http://www.adobe.com/support/digitaleditions
- Click on Submit a Web case
- This should take you to the customer support portal.
- Choose 'Using a product or service' for the 'Choose Issue Type' drop down list...
- Next select the 'I am an enterprise customer, partner, or developer and have purchased a support plan.' - yes this is not true, but it's the only way to get the ticket started and Adobe should be slapped for putting this under here (It didn't used to be).
- This will cause 'Choose Products' to show up - select 'Additional Products' and then select Adobe Digital Editions and then hit continue.
This should take you to a form to fill out - make sure to put the full and complete error message (which contains the number version of your user id - which will make sure they get the right account) in the details box.