I've been deploying a war to Solaris for a while now and recently updated warbler to the newest version. If you use warbler 0.9.13, it will use jruby-1.3.0RC1 which has a known and fixed bug which shows itself with an error like this:

Fcntl not supported on this platform which is a RackInitializationException

This bug has been documented here. If you use warbler, it won't work on Solaris unless you of course use an older version of warbler or you replace the jruby-1.3.0\lib\ruby\gems\1.8\gems\warbler-0.9.13\lib\jruby-complete-1.3.0.jar with the new one. Thanks to the warbler team for your hard work.