We will quicker results troubelshooting your shipping issue.
To do this, we need to know the full request being sent to the shipper and the Full response comming back.
Add this code to your page to get that information back:
echo("The Full request is: ".$_SESSION['eCart1_USPS_FullRequest'];
echo "<br/>The full response is: " . $_SESSION["eCart1_USPS_FullResponse"];
If you cart is named differently, you will need to change the session variable names.
if you could also post back a copy of your cart include file, and the file you have applied the ups behavior to, that will help as well.