It may be bad or perhaps it was written with a larger block size? I don?t recall what tar does if the tape was written with a record size larger than the default. You might try using dd if=/dev/st0 bs=65532 of=... on the tape to see if you can read it at all. I don?t recall what the maximum record size on these tapes are, but it seems like it isn?t a full 65KiB. Also, make sure the drive is not configured for fixed block mode.