i have to agree with Puzz,

installing beta 8 to One copy of VI will not and can not have an impact on the other copies.
files do Not get installed outside the VI directory tree.

something else is causing the problems, a firewall or anti-spy-ware program blocking the port,
or even malware hijacking the port

You may not even know it is there, drive-by malware is becomming more and more common, i had a run in with some myself.
The nastiest stuff like to make use of XP's "superhidden" feature to tuck itself away in plain site...