Are you using standard HDToolBox from WB3.1? If this is the case, you might have to patch it with this:
http://aminet.net/package/disk/misc/HDToolBoxPatchNone of the IDE to CF adapters I have tried so far has worked with standard HDToolBox, I only got it to work by using a patched version.
Another way is by using HDInstTools or OS3.9 HDToolBox, since they don't have this limitation.
BTW. IDEfix/IDEmax must also be patched in order for it to work with CF cards.
