license manager msg "Failed to open TCP port # in license"How to c

I'm getting the above message whenever I try to start lmgrd.exe for ArcGIS
(have the latest lmgrd.exe available for Vista 64-bit Xeon). The TCP port
listed in the license file is 27004.

This started after I tried to start the campus VPN network this last week,
which I now know is not set up for 64-bit machines. The result was lmgrd just
not loading and no access to the internet (no SSH). The latter I fixed with a
suggestion from MS discussion group 'Windows Vista Networking and Sharing'
(typed 'netsh winsock reset' at dos prompt as administrator).

I don't know what to do about the former.

What can I do to find out what happened to TCP port 27004? Or, can I just
change the TCP port referred to in the license file? How do I tell what TCP
ports are available?

Any help would be greatly appreciated.