Make sure the different accounts are not attempting to connect or listen through on the same port numbers. There may have been a bug introduced not sure, but this is not the first report I've heard of this. It may be worth deleting the LW prefs folder on each account. LW must be closed whilst you do this. But make a note of all your LW settings first because once you open LW next time, you will need to reset all options including days to keep incomplete, connection speed, download location, etc. Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)

Oh btw if you are using Norton, delete the firewall rule setting & reset it. Norton & sometimes some other firewall brand settings seem to go stale when a program is updated.