In truth, you don't need to open a specific port as long as it fits within the range (4000-64000, I think). Just make sure your preferences and firewall have the same port number setting.

In fact, I'd recommend a different port, like 5201, 6799, 8562, etc. for security reasons.

Also, try searching for your criteria again and finding different versions of the file. It could be that all the versions you found before are on machines that are rarely up. It happens to me all the time.