UpdateAccountInfoEx2

Hi,
Im trying to use the UpdateAccountInfoEx2 method to update a users first and last names. It seems to work okay from the API explorer, although I dont get any output/reposnse from the API, but the new first and last names do get saved.
However, when I am doing this in code, and passing the exact same params, I get the following error, and a NULL response.
Any ideas?
Micah

SoapFault::__set_state(array(
   'message' => 'System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at Tessitura.WebAPI.TessituraUser.UpdateAccountInfo()
   at Tessitura.WebAPI.Tessitura.UpdateAccountInfoEx2(String sSessionKey, String sEmail, String sPhone, String sStreet1, String sStreet2, String sCity, String sStateProv, String sPostalCode, Int32 iCountry, String sPhone2, Int32 iPhone2Type, String sFax, String sFirstName, String sLastName, String sMiddleName, String sPrefix, String sSuffix, String sBusinessTitle, Int32 iEmailIndicator, Int32 iMailIndicator, Int32 iPhoneIndicator, String sHtmlIndicator, String sGender, String sGender2, String sFirstName2, String sMiddleName2, String sLastName2, String sPrefix2, String sSuffix2, Int32 iOriginalSourceNumber, Boolean bUpdateSalutation, Int32 iAddressTypeOverwrite, Int32 iEaddressTypeOverwrite, String sEsal1DescriptionOverwrite, String sEsal2DescriptionOverwrite, String sLsalDescriptionOverwrite, Int32 iConstituentTypeOverwrite, Int32 iNameStatus, Int32 iName2Status)
   --- End of inner exception stack trace ---',
   'string' => '',
   'code' => 0,
   'file' => '/Users/micah/Development/you-cooperhewitt/www/include/lib_tessitura_soap.php',
   'line' => 56,
   'trace' => 
  array (
    0 => 
    array (
      'file' => '/Users/micah/Development/you-cooperhewitt/www/include/lib_tessitura_soap.php',
      'line' => 56,
      'function' => '__call',
      'class' => 'SoapClient',
      'type' => '->',
      'args' => 
      array (
        0 => 'UpdateAccountInfoEx2',
        1 => 
        array (
          0 => 
          array (
            'bUpdateSalutation' => true,
            'iAddressTypeOverwrite' => 0,
            'iConstituentTypeOverwrite' => 0,
            'iCountry' => 0,
            'iEaddressTypeOverwrite' => 0,
            'iEmailIndicator' => 0,
            'iMailIndicator' => 0,
            'iName2Status' => 0,
            'iNameStatus' => 0,
            'iOriginalSourceNumber' => 0,
            'iPhone2Type' => 0,
            'iPhoneIndicator' => 0,
            'sFirstName' => 'Hello',
            'sLastName' => 'Tessitura',
            'sSessionKey' => 'SB9B1VEG7P0X2B8710MXTSXVC0A9DSGNF300FV14JBUGINJGGG5BEY65VAXE5705',
          ),
        ),
      ),
    ),
    1 => 
    array (
      'file' => '/Users/micah/Development/you-cooperhewitt/www/include/lib_tessitura_soap.php',
      'line' => 56,
      'function' => 'UpdateAccountInfoEx2',
      'class' => 'SoapClient',
      'type' => '->',
      'args' => 
      array (
        0 => 
        array (
          'bUpdateSalutation' => true,
          'iAddressTypeOverwrite' => 0,
          'iConstituentTypeOverwrite' => 0,
          'iCountry' => 0,
          'iEaddressTypeOverwrite' => 0,
          'iEmailIndicator' => 0,
          'iMailIndicator' => 0,
          'iName2Status' => 0,
          'iNameStatus' => 0,
          'iOriginalSourceNumber' => 0,
          'iPhone2Type' => 0,
          'iPhoneIndicator' => 0,
          'sFirstName' => 'Hello',
          'sLastName' => 'Tessitura',
          'sSessionKey' => 'SB9B1VEG7P0X2B8710MXTSXVC0A9DSGNF300FV14JBUGINJGGG5BEY65VAXE5705',
        ),
      ),
    ),
    2 => 
    array (
      'file' => '/Users/micah/Development/you-cooperhewitt/www/include/lib_tessitura_constituents.php',
      'line' => 30,
      'function' => 'tessitura_soap_call',
      'args' => 
      array (
        0 => 'UpdateAccountInfoEx2',
        1 => 
        array (
          'sSessionKey' => 'SB9B1VEG7P0X2B8710MXTSXVC0A9DSGNF300FV14JBUGINJGGG5BEY65VAXE5705',
          'iCountry' => 0,
          'iPhone2Type' => 0,
          'sFirstName' => 'Hello',
          'sLastName' => 'Tessitura',
          'iEmailIndicator' => 0,
          'iMailIndicator' => 0,
          'iPhoneIndicator' => 0,
          'iOriginalSourceNumber' => 0,
          'bUpdateSalutation' => true,
          'iAddressTypeOverwrite' => 0,
          'iEaddressTypeOverwrite' => 0,
          'iConstituentTypeOverwrite' => 0,
          'iNameStatus' => 0,
          'iName2Status' => 0,
        ),
      ),
    ),
    3 => 
    array (
      'file' => '/Users/micah/Development/you-cooperhewitt/www/test.php',
      'line' => 20,
      'function' => 'tessitura_constituents_update_name',
      'args' => 
      array (
        0 => 'Hello',
        1 => 'Tessitura',
        2 => 'SB9B1VEG7P0X2B8710MXTSXVC0A9DSGNF300FV14JBUGINJGGG5BEY65VAXE5705',
      ),
    ),
  ),
   'previous' => NULL,
   'faultstring' => 'System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at Tessitura.WebAPI.TessituraUser.UpdateAccountInfo()
   at Tessitura.WebAPI.Tessitura.UpdateAccountInfoEx2(String sSessionKey, String sEmail, String sPhone, String sStreet1, String sStreet2, String sCity, String sStateProv, String sPostalCode, Int32 iCountry, String sPhone2, Int32 iPhone2Type, String sFax, String sFirstName, String sLastName, String sMiddleName, String sPrefix, String sSuffix, String sBusinessTitle, Int32 iEmailIndicator, Int32 iMailIndicator, Int32 iPhoneIndicator, String sHtmlIndicator, String sGender, String sGender2, String sFirstName2, String sMiddleName2, String sLastName2, String sPrefix2, String sSuffix2, Int32 iOriginalSourceNumber, Boolean bUpdateSalutation, Int32 iAddressTypeOverwrite, Int32 iEaddressTypeOverwrite, String sEsal1DescriptionOverwrite, String sEsal2DescriptionOverwrite, String sLsalDescriptionOverwrite, Int32 iConstituentTypeOverwrite, Int32 iNameStatus, Int32 iName2Status)
   --- End of inner exception stack trace ---',
   'faultcode' => 'soap:Server',
   'detail' => '',
))