Question : Problem: Used capacity on tapes is showing 17.8GB, compression ratio 26.9:1.

For about two weeks or so now, under the Devices Tab in Backup Exec 11d it's showing "Used capacity" as 17.8GB of 17.8GB on LTO2 tapes.  The "Compression Ratio" is showing 26.9:1 and seems random.  It just started doing this and I was wondering if anyone else has had this problem.  Very strange.  I'm current on all updates and that was my first suspected thing but I was current when the problem started.

Answer : Problem: Used capacity on tapes is showing 17.8GB, compression ratio 26.9:1.

Device Drivers are not part of Service Packs. They are not downloaded through LiveUpdate either.
You need to go to the support site (http://entsupport.symantec.com), choose Backup Exec, select Download and select the Driver for your version of Backup Exec. For the 32 bit version of 11d build 6235 you can download the drivers from http://seer.entsupport.symantec.com/docs/289147.htm