If you are still having issues could you please navigate to FileMaker > Edit > Preferences > Plug-ins tab and see if you see the plug-in is checked and listed there.
Also did unzip or extract the contents of the plug-in bundle BEFORE installing the plug-in? Was FileMaker closed when you installed the plug-in? Do you see the plug-in splash screen upon start up? Have you tried closing FileMaker, downloading a clean new plug-in bundle and re-installing?
Can you elaborate on what is meant by "FM11 states it's installed" in order to better clarify and maybe provide a screen shot of the entire setup tab from the demo file? The more details the better I can assist. Please also feel free to contact me directly at (760) 510-1200 xt. 115 if you are still having installation issues.