Netbackup Policy is in queue

Hello Experts,

I had a policy which i fired last night. It has 1 month retention as other policies from last 1 day its still in queue

with the  "awaiting resource xxx-hcart3-robot-tld-0 - No drives are available" message every time..

1:- I cancelled it and again fired it same is happening.

2:- Made the priority to 99999 but to no avail.

3:- Changed the storage unit :(

4:- If i fire other backup policy thats go to active state in a jiffy.

Pls suggest how to troubleshoot.

Server is on 7.6 Windows and these are solaris flat files backup.

Thanks,