I got converted WSDL to PHP script but something is not working very I am trying to connect <http://www.regcheck.org.uk/api/reg.asmx?wsdl>, but getting this error

```html
Array ( [RegCheckServiceCheck::Check] => SoapFault Object ( [message:protected] => System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.NullReferenceException: Object reference not set to an instance of an object. at webtropy.CarReg.Check(String RegistrationNumber, String username) in c:\inetpub\wwwroot\regcheck.org.uk\api\reg.asmx:line 26 --- End of inner exception stack trace --- [string:Exception:private] => [code:protected] => 0 [file:protected] => C:\xampp\htdocs\Check\RegCheckServiceCheck.php [line:protected] => 32 [trace:Exception:private] => Array ( [0] => Array ( [file] => C:\xampp\htdocs\Check\RegCheckServiceCheck.php [line] => 32 [function] => __call [class] => SoapClient [type] => -> [args] => Array ( [0] => Check [1] => Array ( [0] => RegCheckStructCheck Object ( [RegistrationNumber] => [username] => [result:RegCheckWsdlClass:private] => [lastError:RegCheckWsdlClass:private] => Array ( ) [internArrayToIterate:RegCheckWsdlClass:private] => [internArrayToIterateIsArray:RegCheckWsdlClass:private] => [internArrayToIterateOffset:RegCheckWsdlClass:private] => ) ) ) ) [1] => Array ( [file] => C:\xampp\htdocs\Check\RegCheckServiceCheck.php [line] => 32 [function] => Check [class] => SoapClient [type] => -> [args] => Array ( [0] => RegCheckStructCheck Object ( [RegistrationNumber] => [username] => [result:RegCheckWsdlClass:private] => [lastError:RegCheckWsdlClass:private] => Array ( ) [internArrayToIterate:RegCheckWsdlClass:private] => [internArrayToIterateIsArray:RegCheckWsdlClass:private] => [internArrayToIterateOffset:RegCheckWsdlClass:private] => ) ) ) [2] => Array ( [file] => C:\xampp\htdocs\sample-regcheck.php [line] => 46 [function] => Check [class] => RegCheckServiceCheck [type] => -> [args] => Array ( [0] => RegCheckStructCheck Object ( [RegistrationNumber] => [username] => [result:RegCheckWsdlClass:private] => [lastError:RegCheckWsdlClass:private] => Array ( ) [internArrayToIterate:RegCheckWsdlClass:private] => [internArrayToIterateIsArray:RegCheckWsdlClass:private] => [internArrayToIterateOffset:RegCheckWsdlClass:private] => ) ) ) ) [previous:Exception:private] => [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 webtropy.CarReg.Check(String RegistrationNumber, String username) in c:\inetpub\wwwroot\regcheck.org.uk\api\reg.asmx:line 26 --- End of inner exception stack trace --- [faultcode] => soap:Server [detail] => ) )
```

I am sure something is missing in config files, mybe someone got idea ?