VMware windows host backup failing : 13

Hi,

 one of my critical producation server vm [ windows ] backup started failing since last couple of days . no changes made on our side and vm team telling the same. i can see in the vcenter task&events of vm that snapshot is created.

Master: Solaris10 version 7.5.01

Media: Solaris10 v 7.5.0.1

VMhost: windows 2003

Backup method: backup host 

any help is appreciated.

thanks