Join Date:Joined: Jan 2008
That shouldn't be a problem, since the Sprint number just replaces your GV number. I'd check all of your forwarding settings in GV to make sure that the Google Chat is set as one of your forwarding phones (make sure that the checkbox is checked next to it in your Voice Settings > Phones tab, and that you don't have any time restrictions for the forwarding by clicking Edit). Similarly, check to make sure that you don't have any special rules on the specific contact or contact group that you are trying to initiate the call from.
I haven't messed with GrooveIP on the tab, but that'd be a good place to start if you haven't verified that already.