As I had a few issues with this I thought I would follow up with some details. This follows on from the topic on jivesoftware.com
Extracting the application TAR file may fail on Solaris (checksum error)
The recommended fix for this is to install the latest GNU tar program, available from the GNU software websites.
A very useful site is http://www.sunfreeware.com which contains a bundled version of gnu tar with instructions on how to install using pkgadd. Installing this solved my problem, only catch make sure you are actually using /usr/local/bin/tar afterwards and not usr/local/sbin/tar
Hope this helps