I just installed Firefox 1.5.0.5 on FC5 (See another thread in re installing an earlier version of the libstdc++).
Trying to install Flash 7 from Firefox--it appears to install, but does not work.
Also tried a manual install--same pattern.
In PCLinuxOS, I installed v1.5.0.4 and flash was working out of the box.
Testing this on the dreamlinux site--
http://www.dreamlinux.com.br/english/index.html