http://bugs.winehq.org/show_bug.cgi?id=8034
--- Comment #4 from Dan Kegel dank@kegel.com 2008-10-25 16:12:35 --- The latest Flex Builder is version 3. Old versions are still available from http://www.adobe.com/support/flex/downloads_updaters.html In particular, this bug is about http://flexorg.wip3.adobe.com/flex201/FlexBuilder_201_Installer.exe (sha1sum 01559050fc0efc1bff1325595b4dc5438f99ccc0 ).
I suspect your success was with Flex Builder 3; that does install for me.
Flex Builder 2 still doesn't quite, though now instead of crashing, the installer puts up blank windows. They seem to be live - random clicking in them sometimes gets them to the next step - but not very usable.