I once had a specific zone misvbehave and liked to never figure it out--and of all things it was freaking Port Windhurst when I stepped off the bleeding Airship. It wound up being the damnedist thing....firewall was blocking an SE server. They had done some reworking of the servers or something and a new block of IP's was showing up in my logs....sure enough, whois query pointed to SE. Added them to the exception list and voila, no more timeout on "Downloading Data" black screen.

I have a 4850 (same family) and am still using the 9.1 drivers since they haven't really given me any problems...but, I'm on XP. If it's one specific zone that is crashing with no Windows error (just a message from POL about no response from server, etc) than it may be a networking problem and not your graphics card.

Sounds kinda like Yukichibi may be facing a similar netorking problem I've seen in the past, not sure. Might want to check your router/firewall/etc. logs to see if something is getting blocked in these IP blocks:

202.67.48.0 - 202.67.63.255

124.150.152.0 - 124.150.159.255
(when this happened to me, it was an IP in this range)