There is a now a new FAQ entry on problems installing/updating Mylar:
http://eclipse.org/mylar/doc/faq.html#install-failure
The most common issue has been trying to run Mylar in a 1.4 VM. David
Orme also reported a problem automatically updating and getting the 3.2
version installed into 3.1 (due to the Bugzilla Client update site
getting used, discussed here:
http://dev.eclipse.org/mhonarc/lists/mylar-dev/msg00146.html).
If you experience any install/update problems it's easiest to reinstall
by following the steps in the FAQ.
Mik