a) If you don't have GNU tar, just use 'bunzip -c file.tar.bz2 | tar tvf -' (or xvf -). Obviously you still need bzip2 installed.

b) The file name may be incorrect. Use 'file mystical.fiilename.strange.extension' and see what it tells you. It should be able to identify it as e.g. a gzipped file, or just a plain tar file, for example.