Need help quick!

i've just been changing a few icons on my Galaxy S2 home screen. everything has been running great, had no problems whatsoever until i tried to access the market this afternoon.
the error im getting is that i need to set up or sign into my gmail account, so i go ahead and chose sign in, then it says:
"Can't establish a reliable data connection to the server.
This could be a temporary problem or your SIM card may not be provisioned
for data services. If it continues, call Customer Care."

ive searched all day on the net for a fix, tried unmounting the sd card, removing the sim, signing in via youtube, but nothing works.
what i have noticed is that, in the accounts settings, my gmail address is missing as well as my talktalk account (samsung account is there though)
now, i must say that while i have been messing around with stock icons, i havent touched anything google related, or indeed deleted any apk's.

when i try to add ANY email account, i get messages like 'unable to contact server' etc

ive reflashed my firmware as was suggested in another forum, but that hasnt fixed it either.

i have an idea though, but will it work.....if i set up my accounts on my girlfriends galaxy ace, could this be copied to my phone?

also, what apk file stores these settings, i have a sneaky feeling they have either been deleted earlier or corrupted somehow.