The USPS error means that the $WAGLOBAL_USPS_Server you entered does not use the Version 3 of the rate lookup API:
$WAGLOBAL_USPS_Server = "https://secure.shippingapis.com/ShippingAPI.dll"
try setting that to this instead:
$WAGLOBAL_USPS_Server = "http://production.shippingapis.com/shippingapi.dll";
Was the UPS Error on a separate test? setting the globals to:
$WAGLOBAL_Shipping = 3
should only use USPS and bypass UPS. You should not be getting this error.