It seams to me that it is JSF2 problem and not GlassFish. I tried to use JSF2.1.0-b06 and I got the same massage as you, but I use Tomcat6. The same message appears when using 2.1.0-b04. After I switched to stable release JSF2.0.3, the message is gone. Probably GlassFish 3.1 (beta) uses JSF2.1.0 (beta) and that is the reason of this message. I don't have GlassFish 3.1 and I can't check this, but you can try to change JSF libs with stable one.
Regards,
Aleksandar.
[Message sent by forum member 'x3msk8er']
http://forums.java.net/jive/thread.jspa?messageID=486107