I'm trying to delete a user through User Accounts in the Admin section, and each time I get the error "Error Deleting User".  There are no errors in the event log, but each time the deletion fails, it removes the Subscribers and Registered Users role from the user.  This problem only happens with 2 users that registered with the portal a several months ago.  All new accounts created don't have any problems deleting.  I am using DotNetNuke version 04.08.03.  Any help to fix this problem or delete this user would be greatly appreciated.

I assume there is a 3rd party module, which placed a foreign key on the users table, preventing deletion of the user or portaluser record. check, whether the user contributed to a forum, blog etc on your site and remove those records first.

Sebastian was right.  There were refrences to the user in the tables for the store that comes with DNN.  Once I deleted the refrences, I was able to delete the users.  Thank you for your help.