HTTP error: U get hhtp error when ur passing wrong parameters. And http error can be of any kind of http error.
DNS error: domain name server.......server which stores all the domain names and their ip addresses and u try to wrong DNS name
Socket error: socket error occures generaly when there is some connection or communication problem witht he server. when ur response time is running out.
Hope this will give u an some kind of idea about these.
thanks for the Response. ok Ashok tell me one thing are you using the ACT (Application Centre test tools for performance testing.) if yes please let me know how can i use it for the application not for the Web application. and how can i know in the application these http,DNS, Socket errories appear.