I ran into an issue getting Flash working with Flock browser. Being a tinkerer, I found out that you can just copy the link for flash from /usr/lib/firefox/plugins and paste it into the plugins folder of Flock(/home/user/Documents/flock/plugins in my case).
So, hopefully this helps in the adoption of using Flock/Flash. Quite a quick fix as well.
Since a lot of traffic seems to come looking for flash fixes for ubuntu, I figure I should expand on this entry some. The file you are looking for is typically called libflashplayer.so and it isn’t always in the above location. It can also be found in /usr/lib/flashplugin-installer/ as well.
Another option you have, if you used apt-get to install the adobe-flashplugin package, you will find this same libflashplayer.so file in /usr/lib/adobe-flashplugin and can copy this file over to flock/plugins/ directory as well.
Further questions/help feel free to reply here or email me, firstname.lastname@example.org.