the shipping code looks correct to me.
Hmmmm, thats strange, the request and response from USPS are not coming through. Try using this code instead:
echo("<br />Full Request: ".$_SESSION["Kyla_USPS_FullRequest"]);
echo("<br />Full Response: ". $_SESSION["Kyla_USPS_FullResponse"]);
If the Request and response are still not coming through, please send a copy of your WA_eCart folder.