A qualified Yes
On the orienteering Attackpoint forum, search OCAD Mac Linux for the latest.
Mac
OCAD does run on Intel Macs with appropriate middleware such as Virtual PC or Parallels Desktop. For middleware discussion, read this Attackpoint forum article.
Linux
OCAD seems to run just acceptably for some users according to the Attackpoint forum contributors. It would pay to monitor this forum to see if anyone reports a trouble free operation with certain middleware.