Hi,
Try performing a manual duplicate backup :
How to configure duplicate jobs in VERITAS Backup Exec (tm) 9.x / 10.0 for Windows Servers
http://seer.support.veritas.com/docs/256096.htm
Have you tried running a job directly to SDLT ?
Is first backup to Disk Job successful ? or do you get any error or?
Update us on the same and revert for any further Query
Hope this will help you
Thank you
Gauri