Error with sense data on PE 1420SC

[Karl Zander]

Our server is going off-line just as tape backup finishes.  syslog shows 
this

kernel: st0:  Error with sense data:  <6>st:  Current: sense key=0x5
kernel:       ASC=0x20  ASCQ=0x0

And then the server is off-line. 

The tape backup unit is a Seagate Model STT3401A

Kernel is 2.6.16-gentoo-r6

Is the "sense data" error indicating a hardware problem with the tape 
drive?  Or is it indicating I have something incorrect in my kernel? 

--Karl