account doesnt exsist

i was workign on a trade with someone then after i confirmed it, i tried emailin ghim back but i kept gettign a user account doesnt exsist message?? any ideas on what happend? if i can email him fianally what should i do

pm a mod, some members were deleted during the host change
they should be able to restore that members account

I had the same thing yesterday, was it a brand new user? he had just signed up and pm'd me, and when i tried responding it said user didn't exist. I just waited an hour and tried again, it worked...