I have found two issues related to the Resurrection Gorge area:
1. The Waterfall Cave (OH5110.ARE) in the underground area of the gorge (OH5200.ARE) can be entered by a single party member. Exiting the cave however requires the whole party to be present. This issue can be fixed by modifying the respective region flags.
2. Even more serious - and a real game stopper without using cheats - is the the location of your 6th party member on the map after leaving the Waterfall Cave. He will be trapped in a small patch that is separated from the rest of the map. Without teleporting him via Ctrl+J he will be stuck there forever. This is most likely a search map issue.