Hm ..I just realized also that you managed to post in the phex forum, so a moderator might move this.. and if your friend comes here looking for you they will not look in the Phex forums. (Phex is a different application similar to Limewire)
The Limewire chat feature, as is, is somewhat of an afterthought, and for me has one useful side effect, in that it makes it easier to connect to and browse hosts that have chat enabled... I think. It is not MSN or Yahoo chat, and the features of those programmes can not be expected of Limewire chat. Treat it as a nice surprise if it works.
In Tools>options>filters, you will find your block list for hosts, and also search terms, and something else which I don't have on my version
As I said, you must have some idea of what they were sharing, and a search for something relevent is your best bet. I repeat searches often and the same bunch of hosts are always cropping up, provided they are on line.
If you "met" this person through Limewire, I assume that some connection with the files one of you were sharing was the trigger.
If you closed Limewire, I suspect that any information that MIGHT have been saved temporarily, will have been removed, but MIGHT is the main word here anyway.