Check out whether they have permission issues on the SQL side. As odd as it seems, a regular Windows authenticated SL user does *not* have read access to the SQL tables, even though they can use the SL client application with no problem at all. This is so by design.
SL uses a not so well known SQL feature called Application Role, so an authenticated user can access the data only through the SL client. This prevents tampering the database through Excel, Infopath or any tool easily available.
This also prevents running SQL scripts on the side, like backup, index rebuild or replication tasks.
The thing with this approach is that the TI dept may misdiagnose a permission issue saying "I know the permissions are right, since SL works".
In order to run maintenance SQL script, you should setup custom SQL permissions, or use the sysadmin role.