Email him and ask him why.Perhaps he does not mail to your area.Are you in the US? Is he/she?
If you are out of country then perhaps that is why you are blocked and you are thought to be way too much effort for the seller to mail to.Drives me nuts when that happens and makes absolutely NO sense.
If that is the reason you might be able to plead your case.Worse case scenario you could ask a fellow member to bid for you?