Do you have a reason for upgrading the IOS, if not
I would suggest a downgrade to the former image or to
new image available for download on cco.
Also the ICMP unreachable, might mean the ip address
sent in the h225 call set up as the sation h323 ipaddress
might not be reachable. I would think the loopback address was used in this
case and can't be reached.
If that the case just put the loopback address in your routing protocol
or use static route pointing to the right next-hop.