How to check/test .tar.bz archives?

First test bzip2 compression, It should output OK.

bzip2 -tv FILE.tar.bz2

Next uncompress the tarball, to get just the tar.

bunzip2 FILE.tar.bz2

Finally verify the tar file,

tar -tvWf FILE.tar

Truthfully the best indicator of a problem, is a failed extraction. Hopefully you can narrow down the cause. I should also mention I have had the occasional archive fail verification, yet still correctly extract.