Are you trying to file a Canadian tax return or a U.S. tax return? If you are filing a Canadian tax return, see Lisa995's answer above. If you are filing a U.S. tax return, are you a U.S. citizen or resident alien? If not (if you are a nonresident alien), you have to file Form 1040NR, which TurboTax does not support.
If you are a U.S. citizen or resident alien, where exactly is TurboTax asking for your zip code? It can't be logging in. You already logged in in order to post this question. Are you on the screen that says "What's Your Home ZIP Code?" The note below the space for the Zip code tells you to just click Continue without entering anything if you live in another country.