N.A. doesnt mean not available..
It means Not Applicable in the context of the Plugin Manager you are seeing that message in...
So...
Make sure you have downloaded all the essential and whatever additional content you wish...... (Id recommend all of it if you have the free disk space on your system drive) via the Logic Pro menu item, Download Additional Content..
Check the little disclosure triangles for each section to ensure it's all been downloaded... and dont rely on the little button in the bottom left hand corner...
Finally, as a tip: Go to Logic pro X's preferences and turn on All the advanced tools if you have not already done so. Now Logic will work in the full 'Logic Pro X' mode and not the heavily cutdown and limited 'Garageband Pro' Mode...
Additional:
I highly recommend Edgar's excellent visual guides to Logic pro X to help you understand how LPX works and how best to use it....
http://www.dingdingmusic.com/DingDing/Manuals.html