I think you need to supply more info. I assume you mean Ubuntu 9.04? If so which flavor? Ubuntu (Gnome desktop), Kubuntu (KDE desktop), Xubuntu (XFCE desktop), etc.? The tools for printer setup are different unless you use CUPS. Have you checked it works from a different PC? Are you using a hub, or router? Does the cable work? Have you looked at the info on the Brother website?
There were changes in the way printer drivers are handled between Ubuntu 8 & 9.