I am using a broadband connection. i am able to connect it for the first time i open the system but when i disconnnect it and again try to connect i will get this error. I am using windows 7 ultimate 64-bit OS. Then for several times i have to eneter the username and password then it will connect if still it doesnt connect i have to restart the system then it will connect. Please suggest.

If I understand you correct, you are connecting to a remote computer from your local computer. I have experienced this when a remote computer goes into Power Saving Mode. Try disabling Power Saving / Hibernation / Sleep Mode / etc. on the remote computer, and I have a feeling you won't have this issue anymore.