From memory I downloaded the .tar.gz for Linux from Adobe.com, extracted it, and moved it to /usr/pluto/diskless/##/usr/lib/adobe-flashplugin/libflashplayer.so because
dcerouter_1019065:~# ls -l /usr/pluto/diskless/##/usr/lib/mozilla/plugins/
lrwxrwxrwx 1 root root 37 2011-07-04 23:21 flashplugin-alternative.so -> /etc/alternatives/mozilla-flashplugin
dcerouter_1019065:~# ls -l /usr/pluto/diskless/##/etc/alternatives/mozilla-flashplugin
lrwxrwxrwx 1 root root 44 2011-07-04 23:21 /usr/pluto/diskless/83/etc/alternatives/mozilla-flashplugin -> /usr/lib/adobe-flashplugin/libflashplayer.so
dcerouter_1019065:~# ls -l /usr/pluto/diskless/##/usr/lib/adobe-flashplugin/
-rw-r--r-- 1 root root 12110428 2011-04-13 11:30 libflashplayer.so
With multiple media directors, I would perform the work on the DCERouter and change the /##/ to your actual media director numbers.
Standard disclaimers apply / YMMV
Joseph Hume
F1 for HELP