I have Elements 11 for Mac and have downloaded and installed demo plugins of AnarchistSuite and Texture anarchy (http://www.digitalanarchy.com/texture/tutes.html) and also several plugins from here (http://www.richardrosenman.com/software/downloads/).
The anarchy plugins come with an installer which I ran without error, the richardroseman plugins don't come with an installer, but I copied them to /Applications/Adobe Photshop Elements 11/Support Files/Plugins.
I've closed and restarted Elements 11 but can't any evidence of any of these plugins anywhere.
I believe those filters from:
are for windows systems only
Read the fine print at the top of the page under where it says Commercial
Europe, Middle East and Africa