Ant's distibution contains file names that are longer
than 100 characters, which is not supported by the standard
tar file format. Several different implementations of tar use
different and incompatible ways to work around this
restriction.
Ant's <tar> task can create tar archives that use
the GNU tar extension, and this has been used when putting
together the distribution. If you are using a different
version of tar (for example, the one shipping with Solaris),
you cannot use it to extract the archive.
The solution is to either install GNU tar, which can be
found here
or use the zip archive instead (you can extract it using
jar xf).