That fellow says it supports XP but some of the comments disagree with that.
Looks like Umax doesn't support their older parallel port scanners anymore, at least that one. I dug through a box full of old driver disks and found one for the Astra 1220P and this one:
(That's not my listing. I just came across it when I googled for info on my disk.)
Apparently the Umax drivers are called Vistascan. The 1220P has vistascan version 2.43 while the other disk is 3.75--a newer version. So I'm thinking you just need astra vistascan drivers (the newer the better) and not necessarily some specific driver.
The 3.75 version disk has a copyright of 1996-2001 so it ought to cover that old one you have. I was looking at some of the installing ini files on the disk and it looks like it officially only supports 9X and NT but the NT driver might work for XP.
Anyway, the ebay disk is cheap so you might consider ordering one. If you're outside the US the postage is probably more. I could burn you a copy too but my postage and packaging to get it to you would probably be about the same as in the ebay listing.