[Groove IP] No inbound calls on the Viewsonic v350.. no ring

I've installed Groove IP to be able to make and receive Google Voice
calls on the Viewsonic v350. Outbound calls are fine, but inbound
calls never ring.

I have read the FaQ:

http://snrblabs.com/snrb/Apps/GrooveIP/FAQ.aspx

And yes, all calls are forwarded to gtalk (and only gtalk). There is
no other app that could be accessing my account. And do-not-disturb
is disabled.

The only cause that comes to mind would be if the phone has a
power-saving feature that blocks this. I have looked through all the
settings, and the only power-saving controls I have is to decide how
much idle time there is before the screen blanks.

Do other v350 users have this problem?