So you are trying to backup the workstations that have Win7 pre-loaded?
You need either BESR2010 (released NOW), BE2010, or DLO included with BE2010 (release mid-Jan'ish 2010).
The current BE12.5 doesnt support Win7.
On a side note, if you own Symantec's Protection Suite of AV products, you have BESR2010 for desktops already! It's cheaper to buy the security suite with BESR included, than to buy BESR by itself!