Hardware

dear frinds

i am new in solaris field

i am handling a setup haveing v880 m/c with solaris 8 .there we have L100 tape library we are useing veritas netbackup 4.5 version ad backup software

now problem is like that .earlier my friend create some policys to take backup .now during running that policy it giving error
"cannot locate valid new volume for backup"
so i crated new policy and use same volume pool for backup ,now error comes in different way
"cannot attemp for clinet backup"
i was not able to remove that volume pool as well as medias in that pool

if i am adding new medais and put in new volume pool and useing same policy pointing to new volume pool that i created to take backup then its working

so now ,how can i use the volume pools that already created ?
how i can deleted older volume pools and medias in that pool ?