I had a similar problem deploying these printers, however i found using the XP drivers in 2003 does work fine. Not sure why dell doesnt have an installer for this printer in 2003 server, but here you go.ftp://ftp.us.dell.com/printer/R165289.EXE
extract that file, note its destination directory. do not attempt to run the setup.exe, it will fail saying your operating system is not supported.
instead navigate to (if you didnt change the path) C:DelldriversR165289p0nPrinterPCLWINXP
this folder contains the driver you need to install manually.
one stange thing about these lexmark based network printers is the need to select 'local printer' during install, uncheck automatically search for my device, and then create a new TCP/IP port. Use the IP address provided by the network configuration print out you can access on the front panel of the printer. now just make sure to select 'lexmark network card' as the type of network interface. it should now ask you for your printer type, click have disk, and point to the driver folder mentioned earlier.
hope this helps. thanks alot dell.