The problem was (In the meantime I re-installed the whole server) that all WIN95/98 workstations connected to the server had an error messaage during login. It said: could not find share name, or something like that (I use a Dutch version of Windows). The only way to login to those workstations was to bypass the client for microsoft networks. All the shares on the e-smith box did not function in that case ofcourse.
BTW, I enabled domain-logon in the manager.