"You must supply a password to make this connection" with Mac

I have a home network using a wireless router. The network consists of 2
Windows XP Pro, 2 Windows 98 SE, and recently added Macbook. The only
problem I have is that when I try to access the MACbook from either one of
the Windows 98 computers, I get “enter network password" "You must supply a
password to make this connection". There is no password, user combo that
works. Seems to be a well known problem. I've looked through the
MSknowledge base and Googled the problem. It seems that those experiencing
the problem were dealing with Windows 2000 or were having trouble getting
into and XP machine. I don't have any problem going from any of the
Windows machines to each other or TO the MACBook. The Mac goes to all my
Windows computers with no problem. I get the password request only when
trying go to the MAC.

I'd appreciate any suggestions as to what might the Windows 98 SE computers
need or be looking for on the MAC that is causing the problem.

TIA