One thing I have found that that link leaves out is that you need to add a specific username line in your smb.conf file. This username is one of the users of the Mac OSX system.

Your shared segment would look something like this:

[shared]
comment = Shared Directory
path = /Users/Shared
read only = no
browseable = yes
create mode = 755
username = joeshmoe

Only after entering this line was I able to log in to a Mac from a Win98 machine on my network.

I was able to login to a wins 98 machine as long as it had the same username and password as the Mac, but did not have to add that line to the smb.conf file. If you add the line, does the wins 98 machine need to have the same username and password as the Mac?