This is the first report we've heard of that. Odd.
This likely has nothing to do with upgrading instead of clean install - there's really nothing that overlaps in a way that should affect this.
I'm assuming that rebooting helped. Had it been extra-long since your last reboot? Keep an eye on this and let us know if you have it happen again.
One thing to check on is to make sure you're Packet Type: Default or Packet Type: Windows ICMP.DLL. The other methods don't work well on Windows 9x.
Thanks for the report - keep us informed on any other symptoms you see.
- Pete