I've seen that exact same error on other untested tape drives. Have you tried one from the list at http://www.intel.com/support/motherboards/server/sb/CS-028600.htm - Tested Hardware and Operating System List?
Even I have tried with untested LTO4 Drive. Have not tried with LTO3 Drive. But, have found out that LTO4 is not supported on MFSYS25, as running backup can hang the compute module. So, it is advisable only to go with Tested and Certified Hardware, the fact that I learnt lately.