You could have just gone on Freecom's website. It seems like Freecom only do one DVB-T device.
Here are the drivers:
XP
DVB-T USB Driver (only for Art.No.:25451) -
http://www.freecom.com/objects/00012479.zip
DVB-T USB & CARDBUS BDA driver (32 & 64 bit XP) -
http://www.freecom.com/objects/00008584.zip
DVB-T USB & CARDBUS WDM driver -
http://www.freecom.com/objects/00008583.zip
Vista
DVB-T USB Driver (only for Art.No.:25451) -
http://www.freecom.com/objects/00012479.zip
Freecom Hybrid USB Stick driver (32 bit Vista) -
http://www.freecom.com/objects/00011347.zip
Freecom Digital USB & Cardbus DVB-T drivers (32 & 64 bit Vista) -
http://www.freecom.com/objects/00010626.zip
You probably only need one of the above drivers, just make sure you download the right one for your operating system.