You guys have undertaken a very ambitious pbem. 6 players is quite a lot of links in the chain, and links get broken pretty easily.
I suggest that you all abide by a rule that you post in this thread once you have emailed the save to the next player. Without that, it can literally take days to figure out who has which save.
Also, if anyone password protects their civ (everyone should, to prevent accidental espionage), the game admin should be told the password so the game doesn't die if that person goes absent without explanation.
[/ my two cents]