Error 601 in using Dial-Up Internet connection

Hi! I am using Windows 98 (as I have got slower computer machine) and created a dial up connection on it. It has been quite long time I am using dial up connection without facing any sort of issue though by the time now I am encountering with an error message. Let me try to explain you people what nature of error I am facing the time I try to use VPN. It results me the following error message:
windows dun/rss error 601
"the port handle is invalid."
