I've the same issue and i decided that in next step:
1. Service Manage Engine Service desk plus starts from accout with admin rights.
2. If you install Service desk on the Windows Serever 2008 or Windows 7 then check NTFS rights on the ManageEngine catalog. I reassign right on the accoun which starts service Manage Engine Service desk plus and nested right on subfolders.
3. If you don't use 'sa' account to db access assign sysadmin right for db access.
1. Service Manage Engine Service desk plus starts from accout with admin rights.
2. If you install Service desk on the Windows Serever 2008 or Windows 7 then check NTFS rights on the ManageEngine catalog. I reassign right on the accoun which starts service Manage Engine Service desk plus and nested right on subfolders.
3. If you don't use 'sa' account to db access assign sysadmin right for db access.