There's never any guarantees re: browsing host.
I suppose temporarily, you could make sure nobody else is uplding from you but I don't know if that's wise or not.
Another thing you can try (if you or they know your ip address; to find out go here: http://www.whatismyip.com/ ) is to add their ip to your connections window as soon as you open LW. Failing that, attempting direct connect & having both your Chats enabled is the best way. Try having more than one copy of that odd named file. eg: make it a document file x 10 copies. Do a document search. Once located, then browse them.