Has anyone ever seen this problem:

I have an IIS server in a DMZ. There is a share on it so the webmaster can modify the web site. The problem is, the webmaster can't map a drive to the server. He gets an error stating the server in the network path can't be found. The kicker is, I can map to it. The difference between our workstations is, his [webmaster's] is Win 98, and mine is Win2k pro. I have tried this on other win9x, win2k, and nt wkstn PCs with the same results. The Win2k and NT PCs could map to the share, and the Win 9x couldn't. Any ideas?