Pretty simple
Do this
su -c 'yum install flash-plugin nspluginwrapper.x86_64 \
nspluginwrapper.i686 alsa-plugins-pulseaudio.i686 \
libcurl.i686'
(from http://fedoraproject.org/wiki/Flash#On_64-bit_Fedora)
Then download the debug version of Flash player (for linux) from Adobe's site. Extract the zip file and replace ALL occurrences of libflashplayer.so on your system with the one you extracted from Adobe's site. Worked for me for FB4 on Fedora 13 (10.1 version at least)