okay, this one seems was easy enough until i almost missed a good solution. i was having this same problem. searching for other forums did no good. lexmark tech support was telling me the same things you all have heard.
i am running Vista Home Premium and i still have the original CD that came with the X4530 when i bought it. CD doesn't work either. go to your system properties. the first section is 'windows edition.' Then 'System', under system type it shows to be 64-bit. I downloaded the 64-bit installer and it went right through. works with the wireless and USB connections on windows vista.
we just got too accustomed to our old XP machines