Your link is returning a 404 error? But I think I know the page you mean, is it this one?
https://helpx.adobe.com/x-productkb/pol ... error.htmlit seems the same as yours to me but hey-ho.
Anyway I followed this and used this code successfully
Freehand MX Win FHD110-58402-67227-68568
I used it for a while then didn't use FHMX on the PC for a period of several weeks, when I went back nothing would open, not even the program? I tried deleting FH and re-installing it but couldn't get it to work, I couldn't even get it to the point where it did ask me for the serial number.
I think I need to borrow an original disk to install it from?