I have the same problem, so I also do wait for an answer...
Thanx, Marko Slovakia
Okay, here's the answer:
Instead of using the stable release of JBoss IDE 1.4 series download the development version (1.5RC1) from this site in Eclipse Update Manager: http://download.jboss.org/jbosside/updates/development
So, start from a non-JBoss IDE Eclipse install and get the development version from the site mentioned above.
Its pretty strange that the development version is more stable than the stable version.
I had the same problem when using Eclipse 3.2.0 (Build id: I20051102-1600). The solution given by karanmg works for that version as well.