createUrlWidget

I am trying to POST a soap XML stream with the createUrlWidget. I'm doing pretty much the same thing for sendDocument and that works, but createUrlWidget will not work. This is the response I get -

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><soap:Body><soap:Fault><faultcode>soap:Server</faultcode><faultstring>Fault: java.lang.NullPointerException</faultstring></soap:Fault></soap:Body></soap:Envelope>

I saw a question by someone else who had the same problem with the exact same response but there was no answer. I don't understand why sendDocument would work but createUrlWidget, which is essentially the same thing with the same tags, does not work