The latest device drivers can be downloaded & installed using LiveUpdate. Else, if you prefer to do it manually, use this link to download http://www.symantec.com/docs/TECH153090 & then run tapeinst.exe to install.

You can also upgrade to BE 2010 R3 SP1.  This will give you all the latest drivers.  Your existing licence keys will work with R3.

Actually R3 + SP1 + Hotfix 167567 (DDI20110915) provide the very latest Device Drivers

We release DDI (Device Driver Installer) pacakges as Hotfixes approximately once a quarter.

We also typically stop providing updated Device Driver packages for older BE builds one DDI release after the new build is available - as such we probably won't be providing new DDI releases for R2.

EDIT: One other point, Symantec don't usually mess with the library driver itself which in a lot of environments will probably be called "unknown medium changer" we usually only provde tape device drivers for the tape drives inside the library.