It is hard to say what is going on here but the telco switch is dropping the call becasue we never sent a call proceeding or alerting message back to it. This is not a problem with the T310 timer in CallManager.
On the surface, it looks as if the problem is on the VG200 because CallManager has instructed it to reserve the timeslot for a call via the CRCX, but the gateway is the one that rejects it with a 400 error message which means there was some condition on the gateway that prevented it from setting up the call.
What is the status of the T1? Are there channels that are busied out.
At any rate to get further insight, you would probably need to run the following debug on the gateway to get a sense for why the gateway is having problems processing the call setup
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