HOWTO: The user '{whatever}' does not have permission to register endpoint '{whatever}' on the specified URL
Cause: This happens when you try to create an HTTP ENDPOINT in SQL Server 2005 because the SQL Server process lacks permissions to register the endpoint with HTTP.SYS.
Fix: Issue the following command before executing the CREATE ENDPOINT
| EXEC sp_reserve_http_namespace N'http://{hostname}:{port}/{path}' |
credit: http://sqljunkies.com/WebLog/ktegels/archive/2005/04/14/11616.aspx