Cf. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=561411
$ file xtitle-1.0.1.tgz
xtitle-1.0.1.tgz: gzip compressed data, was "xtitle-1.0.1.tar", from Unix,
last modified: Thu Dec 10 15:25:49 2009
$ gzip -dc xtitle-1.0.1.tgz
xtitle-1.0.1.tgz does not have compressed suffix -- skipping
tar: This does not look like a tar archive
tar: Exiting with failure status due to previous errors
SUGGESTION
Please add support to recognize *.tgz and *.tbz2 suffixes as valid
standard compressions extensions. E.g. the *.tgz has been widely in use
since early days of Slackware.
Jari