Why not but it from an Amiga dealer? At least you know it will work. I bought a CF adaptor with a 4GB card for something like 30 Euros from Vesalia for an A4000 which worked fine.
http://www.vesalia.de
It certainly could be the compact flash card itself that does not work. I purchased an adapter from Amigakit that works well, but not with some flash cards!
