From: <glassfish_at_javadesktop.org>
Date: Wed, 16 Jun 2010 21:33:09 PDT

Probably, you need to define <resource-ref> in your component's descriptors
eg: web.xml and sun-web.xml for web component
or
ejb-jar.xml and sun-ejb-jar.xml for EJBs.

Following blog might be of help which explains about defining resource-ref :
http://thestewscope.wordpress.com/2008/01/08/glassfish-v2-ur1-and-mysql-connection-pool/
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