OK. I'm bewildered!

I previously said that I prefer to understand what and why I'm doing something. I don't understand but it is working now.

Here is a seriously abbreviated version of what I had previously done:
-installed various P2P & torrent programs - they wouldn't connect on the XP machine
-uninstalled both ZoneAlarm & AVG virus scanner - they still didn't work.
-reinstalled both ZoneAlarm & AVG virus scanner - they still didn't work

Here is what I just did:
-disabled ZoneAlarm (not uninstalled), tried BearShare - didn't work
-uninstalled BearShare 4.5.0.63, installed BearShare 5.2.5 - It WORKED!
-re-enabled ZoneAlarm - It still works!
-I checked the bittorrent client in Opera and it now works too!

It doesn't make any sense and I don't understand why but it is working.

BTW - Once it was working, I checked my event log and found one 4226 entry - (TCP/IP reached connection limit). I presume that I should use lvllord to increase the number of half open connections. What number would you recommend?