InfoPath cannot connect to data source

Hi all,
I have an InfoPath form in SharePoint 2007 that has dataconnections to SQL server DBs. I have a group of users that have been using them for the past few months with no problem. The permissions on the site have not changed but users can no longer access the Data connections. They get a “failed connection to data source” error popup with “work offline”, “try to connect” and “show details”. When I click on Show details it says the DC cannot access the query, “Access Denied”. After going around a few times I reset the Internet options back to defaults. this worked for 1 person but not all. They all have the same AD groups, and SharePoint rights.
I have a test user in SharePoint that has no rights and is a member of 1 group besides “Domain Users” I granted this user the same rights to the data connection library and the Forms library. He can open the form and the data conections work fine. The users that cannot access the DC are in the same groups as the test user, the SharePoint permissions are the same, some of the real users have more rights than the test users. The data connections are useing a SQL user to connect to the Databases. I can log in as the SQL user and read the tables the connectors read. If the issue was the SQL user no other user would be able to access either. these user have the same issue with data connectors that use integrated security.
This is really driving me crazy, any and all help is greatly appreciated.
TIA,
Joe