Could you capture REST Request/response using firebug/fiddler etc. to see whats going on?
if (useProxy && configData.proxyUrl)
                    {
                        gpService.url = configData.proxyUrl + "?" + gpURL + "?f=json";
                        gp.proxyURL = configData.proxyUrl;
                    }
                    else
                    {
                        gpService.url = gpURL + "?f=json";
                    }
 gpService.url = gpURL;
                    if (gpURL.indexOf("?") != -1){
                        if (gpURL.indexOf("f=json") == -1)
                        {
                            gpService.url = gpService.url + "&f=json"    
                        }
                    }else
                    {
                        gpService.url = gpService.url + "?f=json"
                    }
                    
                    if (useProxy && configData.proxyUrl)
                    {
                        gpService.url = configData.proxyUrl + "?" + gpURL;
                        gp.proxyURL = configData.proxyUrl;
                    }
					
				
			
			
				
			
			
				
			
			
			
			
			
			
		if (useProxy && configData.proxyUrl)
                    {
                        gpService.url = configData.proxyUrl + "?" + gpURL + "?f=json";
                        gp.proxyURL = configData.proxyUrl;
                    }
                    else
                    {
                        gpService.url = gpURL + "?f=json";
                    }
  if (useProxy && configData.proxyUrl)
    {
        gpService.url = configData.proxyUrl + "?" + gpURL;
        gp.proxyURL = configData.proxyUrl;
    }
 gpService.url = gpURL; 
					
				
			
			
				
			
			
				
			
			
			
			
			
			
		https://maps.tnc.org/ecadpubprodanon/rest/services/testextract_auth/GPServer/Extract%20Data%20Task?token=J7xH0dk8hRXP5Bq_YQevwSX7P92kPPLK25IE0dxYDIYp6SFZFJC6lJfTkgDLDrPDorpDog7ohIUV-rLV4QfnFg..and it works differently from this: https://maps.tnc.org/ecadpubprodanon/rest/services/testextract_auth/GPServer/Extract%20Data%20Task?t...