Because the Norton Firewall is being used, the Windows Firewall should stay disabled so that it does not cause conflicts. Since you mention that it is turning itself back on, you could be in need of some Windows updates or there could be some other software conflict.
The first thing you should do is to run Windows Update and make sure that you have the latest Microsoft patches applied. Next, open Norton Internet Security 2009 and manually run LiveUpdate to make sure you have the latest patches applied.
After completing the steps above, follow the instructions in the link below for creating a New Rule.
You will also have to create a rule to allow the ports to be forwarded. Open Norton Internet Security 2009 and go to "Internet Settings."
1. Click Configure next to "Program Control" under "Smart Firewall."
2. In the program list, select the program for which you want to allow or block a specific port, and then click Modify.
3. You can see the Program rules listed for that particular program. By default, 2 program rules are listed for any program which has Internet Access enable; first for TCP & UDP and second only for TCP. Select the rule and click Modify.
5. Now you can customize the Internet access for that specific program. by selecting the "Communications" tab and choose the "Add" button to specify ports, etc. When you are finished, make sure you choose the "Apply" button.
Please let me know if this resolves the issue or if you are still having difficulties.