Thank you for your post.
Are you running 32-bit or 64-bit versions of FileMaker Pro 14? Keep in mind that FileMaker Pro 12/13 were 32-bit applications that used 32-bit plug-ins. If you are now running 64-bit version of FileMaker Pro 14, make sure you get a 64-bit version of the plug-in from the manufacturer.
If you are using 32-bit versions of FileMaker Pro 14, what steps are you taking to install the plug-ins?