mine does the same (win2K, limewire v2.2.4basic) it has been happening since v2.0b

Also, I find that after 2-3 hours my connections stop responding, although I appear to still have my 10 outgoing ultra peer connections. Interestingly, they all appear to have ? as a number of hosts rather than the few that I normally have that report a number of hosts. The only solution is to close the programme and restart.