I have Flash Professional 8 running under crossover 6.2.0 on Ubuntu 8.04 on an AMD 64.
Install is from the Studio 8 CD. Permissions on the CD prevent installing directly from the CD (except for root - not recommended).
First copy the entire CD to the hard disk
mkdir ~/studio8
cd ~/studio8
sudo cp -r /media/cdrom .
sudo chown -R *Install as a non-supported application, browsing to the directory as an alternate CD location. I used a Windows 2000 bottle. It will not install with Win98 bottle as the installer is not recent enough.
Launch Flash Professional install from the CD.
I have had Flash crash once (complete hang when in help documentation, used xkill and restarted). I have not done comprehensive testing, but have done some editing including Actionscript which works fine.