Need help with simple SOAP request

[orikon117]

I am trying to get a simple SOAP request working but I keep getting this error:

Fatal error: Uncaught SoapFault exception: [soap:Server] Server was unable to process request. ---> Object reference not set to an instance of an object.

 

Basically, I should be able to send my credentials to the web service and get the version information of their system. Here is my code, I am using the built-in PHP5 SOAP functions. The error is on the line with $result = $client->About($params);

 

<?php
    $client = new SoapClient("http://XXXXXX.asmx?WSDL");
    $params = array(
'sUserName' 	=> 'string',
'sCompanyName'	=> 'string',
'sPassword'		=> 'string'
    );
    $result = $client->About($params);
?>

 

Here is the WSDL Request I need to send:

 

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <About xmlns="http://XXXXX">
      <oCredentials>
        <sUserName>string</sUserName>
        <sCompanyName>string</sCompanyName>
        <sPassword>string</sPassword>
      </oCredentials>
    </About>
  </soap:Body>
</soap:Envelope>

 

Here is the response:

 

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <AboutResponse xmlns="XXXXX">
      <AboutResult>
        <sProdName>string</sProdName>
        <sVersion>string</sVersion>
        <sBuild>string</sBuild>
        <sCopyright>string</sCopyright>
      </AboutResult>
    </AboutResponse>
  </soap:Body>
</soap:Envelope>

 

The section in the WSDL file:

 

<s:element name="About">
  <s:complexType>
    <s:sequence>
      <s:element minOccurs="0" maxOccurs="1" name="oCredentials" type="tns:Credentials"/>
    </s:sequence>
  </s:complexType>
</s:element>

<s:complexType name="Credentials">
  <s:sequence>
    <s:element minOccurs="0" maxOccurs="1" name="sUserName" type="s:string"/>
    <s:element minOccurs="0" maxOccurs="1" name="sCompanyName" type="s:string"/>
    <s:element minOccurs="0" maxOccurs="1" name="sPassword" type="s:string"/>
  </s:sequence>
</s:complexType>

<s:element name="AboutResponse">
  <s:complexType>
    <s:sequence>
      <s:element minOccurs="0" maxOccurs="1" name="AboutResult" type="tns:CAbout"/>
    </s:sequence>
  </s:complexType>
</s:element>

<s:complexType name="CAbout">
  <s:sequence>
    <s:element minOccurs="0" maxOccurs="1" name="sProdName" type="s:string"/>
    <s:element minOccurs="0" maxOccurs="1" name="sVersion" type="s:string"/>
    <s:element minOccurs="0" maxOccurs="1" name="sBuild" type="s:string"/>
    <s:element minOccurs="0" maxOccurs="1" name="sCopyright" type="s:string"/>
  </s:sequence>
</s:complexType>

 

I have also tried other things like $result = $client->About->oCredentials($params);

Any help would be greatly appreciated. Thanks in advance!