Security Against Port 4899 Abuse

Hello Mates,

Well i am in mauritius and we run some windows 2000 servers with sp4 and all updates. We are connected to the internet and used Norton Corporate Antivirus. Unfortunately i am having some people accessing my servers using the port 4899 vulnerability as i use Remote Admin V2.1.
Can you people please suggest a way i can protect myself and my network againts that kind of intrusing