It is very strange that I'm having the same problem, but instead my server is running Windows XP.
Setup:
Same wireless router (SMC 7004AWBR),
iBook running OS X 10.2.8 w/ Airport card.
WinXP box with latest patches, wired.
Win2000 laptop with latest patches, wireless.
Every permutation works, except the iBook (wireless) can't see the WinXP box iTunes shares, although the WinXP box can see the iBook's shares.
Moving the iBook to wired makes the WinXP iTunes share appear.
win2000 can see winXP, and vice versa.
win2000 can see iBook, and vice versa.
Your fix (to upgrade the server to OS X 10.3) won't work for my XP box obviously.
Any insight into the root cause?