Not Able to Expire the Tapes

Hi All,

We are running NBU on 7.0 on Win2k8 machine, we had some set of tapes which are used April 2014, and now when i try to reuse them its shoing some data, and when  i try to expire the Tapes its showing an error like ""requested media id is not assigned to this host in the EMM database" is received.", could any one help me on this.