postUrl not working

postUrl not working

I always get internal exception from postUrl,can anybody help me?the script work well several days earlier.

helloworld = map({ "Airway_Bill_Number" : input.Airway_Bill_Number });
result = postUrl("http://vytalhost.com/zoho/shipmentValidation.do?Declared_Value=" + input.Declared_Value, helloworld);

I'm sorry,but I,m dying to solve this problem,please help me.