error installing printer with printui.dll

I am trying to install programatically a printer with these 2 commands:

C:\Windows\system32\rundll32.exe printui.dll,PrintUIEntry /ia /m "Xerox Phaser 1235 PS" /h "Intel" /f "%windir%\inf\ntprint.inf" /u

C:\Windows\system32\rundll32.exe printui.dll,PrintUIEntry /if /b "FlashProspectus" /f "%windir%\inf\ntprint.inf" /r "c:\flashprospectus.ps" /m "Xerox Phaser 1235 PS"

It gives me on some PCs: "INVALID ARGUMENTS" on step2 (step1 works)
What can be wrong ?