Yes I have ran the checkout wizard more than once. But I always delete all the pages that it creates from my side and the server before running it again. Here is the code that I am using. What is the shipper number? Also I have set ecart object to OZ but confirm page is set to LBS for UPS.
$Shipping_Parameters["CarrierCode"] = "03";
$Shipping_Parameters["PickupType"] = "01";
$Shipping_Parameters["CustomerClass"] = "none";
$Shipping_Parameters["ShipperNumber"] = "";
$Shipping_Parameters["ShipperCity"] = "Houston";
$Shipping_Parameters["ShipperState"] = "TX";
$Shipping_Parameters["ShipperZip"] = "77024";
$Shipping_Parameters["ShipperCountry"] = "US";
$Shipping_Parameters["ShiptoCity"] = "".((isset($_POST["shipping_city"]))?$_POST["shipping_city"]:"") ."";
$Shipping_Parameters["ShiptoState"] = "".((isset($_POST["shipping_state_province"]))?$_POST["shipping_state_province"]:"") ."";
$Shipping_Parameters["ShiptoZip"] = "".((isset($_POST["shipping_postcode"]))?$_POST["shipping_postcode"]:"") ."";
$Shipping_Parameters["ShiptoCountry"] = "".((isset($_POST["shipping_country"]))?$_POST["shipping_country"]:"") ."";
while (($Shipping_Packaging == 1 && !$eCart1->EOF()) || ($Shipping_Packaging == 0 && $Shipping_Counter == 0)) {
if (WA_eCart_UPS_IsTrueValue("true")) {
$Shipping_PackageArray[] = array();
$Shipping_PackageIndex = sizeof($Shipping_PackageArray)-1;
$Shipping_PackageArray[$Shipping_PackageIndex]["eCart_Quantity"] = (($Shipping_Packaging == 1)?$eCart1->DisplayInfo("Quantity"):1);
$Shipping_PackageArray[$Shipping_PackageIndex]["IsPackage"] = "true";
$Shipping_PackageArray[$Shipping_PackageIndex]["Quantity"] = "".WA_eCart_FormatNumber($eCart1->DisplayInfo('Quantity'), true, 1) ."";
$Shipping_PackageArray[$Shipping_PackageIndex]["WeightUnits"] = "LBS";
$Shipping_PackageArray[$Shipping_PackageIndex]["PackageWeight"] = "".WA_eCart_FormatNumber($eCart1->TotalColumn('TotalWeight'), true, 1) ."";
$Shipping_PackageArray[$Shipping_PackageIndex]["PackageType"] = "02";
$Shipping_PackageArray[$Shipping_PackageIndex]["SizeUnits"] = "IN";
$Shipping_PackageArray[$Shipping_PackageIndex]["PackageLength"] = "10";
$Shipping_PackageArray[$Shipping_PackageIndex]["PackageWidth"] = "10";
$Shipping_PackageArray[$Shipping_PackageIndex]["PackageHeight"] = "5";