USPS Skullduggery

Been having problems with USPS.
version $Id: usps.php 15881 2010-04-11 16:32:39Z wilt $
Just got off the phone and verified that I was on the production server.
Keeps giving people an empty box with the header "available shipping methods," debug saying "please enter a valid zip code for the sender" and

<Error><Number>-2147219099</Number><Source>Rate_Respond.;clsRateV3.UnpackRateNode;SOLServerRates.RateV3_Respond</Source><Description>Missing value for ZipDestination.</Description><HelpFile></HelpFile><HelpContext>1000440</HelpContext></Error>

But mostly this one :

<RateV3Response><Package ID="0"><Error><Number>-2147219498</Number><Source>DomesticRatesV3;RateEngineV3.ProcessRequest</Source><Description>Please enter a valid ZIP Code for the sender. </Description><HelpFile></HelpFile><HelpContext>1000440</HelpContext></Error></Package><Package ID="1"><Error><Number>-2147219498</Number><Source>DomesticRatesV3;RateEngineV3.ProcessRequest</Source><Description>Please enter a valid ZIP Code for the sender. </Description><HelpFile></HelpFile><HelpContext>1000440</HelpContext></Error></Package><Package ID="2"><Error><Number>-2147219498</Number><Source>DomesticRatesV3;RateEngineV3.ProcessRequest</Source><Description>Please enter a valid ZIP Code for the sender. </Description><HelpFile></HelpFile><HelpContext>1000440</HelpContext></Error></Package><Package ID="3"><Error><Number>-2147219498</Number><Source>DomesticRatesV3;RateEngineV3.ProcessRequest</Source><Description>Please enter a valid ZIP Code for the sender. </Description><HelpFile></Hel
pFile><HelpContext>1000440</HelpContext></Error></Package><Package ID="4"><Error><Number>-2147219498</Number><Source>DomesticRatesV3;RateEngineV3.ProcessRequest</Source><Description>Please enter a valid ZIP Code for the sender. </Description><HelpFile></HelpFile><HelpContext>1000440</HelpContext></Error></Package><Package ID="5"><Error><Number>-2147219498</Number><Source>DomesticRatesV3;RateEngineV3.ProcessRequest</Source><Description>Please enter a valid ZIP Code for the sender. </Description><HelpFile></HelpFile><HelpContext>1000440</HelpContext></Error></Package><Package ID="6"><Error><Number>-2147219498</Number><Source>DomesticRatesV3;RateEngineV3.ProcessRequest</Source><Description>Please enter a valid ZIP Code for the sender. </Description><HelpFile></HelpFile><HelpContext>1000440</HelpContext></Error></Package></RateV3Response>

Any help would be appreciated.

'nother problem popped up - international customers are getting 4lbs for a parcel, rather than the 1 lb that's listed for it.

Aphexangel:

'nother problem popped up - international customers are getting 4lbs for a parcel, rather than the 1 lb that's listed for it.That sounds like "tare" which is an addition to allow for packaging. You can control that at Admin > Configuration > Shipping/Packaging > Package Tare Small to Medium - added percentage:weight

yep, and it looks like I forgot to define my zip code. Man, I feel all retarded.
Thanks for pointing me in the right direction!