Salut Krizzy, no worries, it is normal! It is a part of partial file sharing on Gnutella. To avoid corruption, LW will examine the file in many parts to determine unique identity for each one of those parts (each identity is a tiger tree hash). If while you download, a part doesn't have the same identity, LW will try to download it again unaffecting the entire file. That way, corruption is avoided in many cases. So LW always requests the tiger tree before downloading files to verify them while LW downloads them. All Gnutella clients normally have this behavior.
Ciao
