Sorry folks, my mistake.
I found that I had not created my WEB-INF/web.xml file correctly; I had forgotten to add a <resource-ref> configuration to enable my datasource.
I guess Tomcat works w/o this configuration, since they use the <Resource> tag in META-INF/context.xml.
So you were right, cobrien, "set up a resource-reference" was the answer for me.
Oh, and another culprit was, you need to recreate your JDBC resource once you make changes to its underlying connection pool (restarting Glassfish won't help).
I still think that the error message(No suitable driver) is misleading and incorrect, though.
Thank you all for your time and advise.
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