ftp problem

I am dialing in via ras to the 2003 server. Then I am connecting to an nt4 server via ftp. This works fine for the 1st user. The 2nd concurrent user connects fine to the 2003 server, but is unable to get to the ftp site. Both users are using the same user id and password. Any ideas what I would need to change to have the 2nd user also ftp to the nt4 box?
Thank you for your help.