WP e-commerce USPS shipping error

Hi, I installed the wp e-commerce plugin in May of 2012. Everything about it I have loved; adding products, configuring all the settings, etc.

I have added about 30 products thus far. I have the shipping set to USPS and the only payment method I’m using right now is manual (check or money order).

The problem is… when I try out the cart just as a customer coming to my site would, I add an item to my cart (all items are 4 oz, i havnt put in dimensions), go to the checkout page and go down to where it says to calculate shipping. I plugin what country (US) state (VA) and zip code (*****) im ordering from and it should tell me to send a check to such-and-such address. All it does, though, is tell me “Sorry, online ordering is unavailable to this destination and/or weight. Please double check your destination details.”

It duznt matter what country plugin, the message is always the same. It never gets to the point where the customer fills out their information and submits the order. This is very frustrating! I have tried MANY MANY different plugins for this purpose and none have worked. E-commerce is the one closest to working, but, obviously, its not.

CAN SOMEBODY PLEASE HELP ME!!!
Thanks