You need to post more information about your configuration and code before anyone can help. However, if you are trying to access the datasource from a remote client, the JBoss datasource will not be available. Hence you cannot look up the JNDI binding and you will get a "name not found"/"datasource not bound" exception.
Otherwise if this is not your situation, do post more information regarding the datasource configuration and the code you are using to access the datasource. That way, people will be able to help you.
Due to the fact that you have provided almost no information I am going to have to assume that you are making the mistake of trying to retrieve the connection from an application running in a different JVM.
Using JBoss this is not possible, database connections can only be accessed from within the JBoss JVM.
If this is not your problem please provide the following:-
Full description of how you are trying to obtain this connection e.g. Where from, code sample...
Error message with StackTrace.
Also check using JNDI View that the connection is bound where you expect it to be.