I have the same problem (build b58g-fcs). This is running a cluster with two instances, each instance on its own machine.
I'd setup the datasource and connection pool, and made sure the datasource had the cluster instance listed under the selected-targets list.
Then I deploy the EAR file (using the GUI), and make sure the target is also set to the cluster instance. Checking the logs, the application fails to find the datasource and fails to start.
I disable, enable, disable and re-enable the datasource (probably overkill), then disable and re-enable the application, and the application starts fine (locates the datasource in JNDI etc).
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