I'm getting exactly the same thing, but with 3 nodes...
I'm using the standard config, but with the relevant parts of the 'all' config copied in. Sometimes (about 1 in 5) it works like a dream. Most of the time however, the new ear successfully deploys on the 'origin' node (ie. the one upon which the new ear file was placed), but fails on the other nodes. The old ear is always undeployed.
I'm using Jboss version 3.2.6.
Is this a configuration thing I need to tweak somewhere?