First, Ramkumar, edit your post and REMOVE YOUR SECURITY KEY! (Or any moderator who has the authority)
Never, ever, post it like that. With it, anyone could do nasty things to your App users. I don't mean to be rude, but that's a big no-no. Just fill it in with randomness next time you want to display a code-chunk that includes your Key.
Secondly, about the error you're getting -- the requestObj.UserId has to be a string of the UserId of a MySpace Member who has installed your Application. Usually, for testing that would be yourself. I checked, and the one you have in the code above isn't your Id, your Id is "330349241" (No, User ids are not secrets -- I took that one directly from the hyperlink to your profile).
And thirdly, am I the only one who finds the title of this thread hilarious?
"Get friends from myspace?"
Never, those people are nuts!