here are my probably naive questions:
1) have you tried installing flash
under wine?
2) If that doesn't work, if by hook or crook (cf. wallcraft above) under Linux you can download the .acsm file, and put it where wine can find it (such as ~/.wine/drive_c or whatever it may be on your system) then, under wine/ADE, load it, it might work.
Once you get the actual epub downloaded, there are ways to remove the DRM. (hint: google something like, oh, I don't know, say "cabbages adept drm" and go from there)
And FWIW I agree with you about DRM. My boss ( a small-press print and ebook publisher) doesn't allow DRM whenever possible. Which is most of the time. Buy your books from such publishers, and --hey, presto-- no problems!
