Check the JNDI data source in the web.xml. Sometimes the data source is empty when the ear gets built and deployed.
Depending on the version you are coming from, you might have to choose to update the profile in configmgr too.
Also, check the schema. Under the dbscripts/modified, find the schema and see if the schema is correct. The schema is usually the same as the user but not always. When the ear is built it may use the schema name even if you don't run the db scripts (I am not certain about this but it's easy enough to compare the actual schema with what's in the script).