Mapping a network drive from Windows to Unix

I am setting up a new server and have gotten it to allow users to logon to their user accounts on other computers. But, when I try to map a network drive from a UNIX server, I get the error message "Incorrect password or unknown username for" the drive. What am I missing doing to allow it to connect? I have made a share in active directory for that drive and have basically copied the other server in every way I can find. But, it will not allow me to map the drive

Matt W.