I am asking you to do the steps again.
Try deleting the .lsi file again from the below location. (Just remember to take a back of existing file)
%User\\AppData\Roaming\SAP BusinessObjects\ SAP BusinessObjects Enterprise XI 4.0\lsi
Note make sure the none of the client tool should be running.
Once done, Try login to UDT and see if you are able to login.
If you are not able to login, try to login from any other machine. This will rule out if the issue is machine specific or it has something to do with your login.
- Kuldeep