garethrhind,
This error almost always happens if you've installed and enabled the JomSocial profile plugin, but don't have JomSocial installed on your Joomla site. If you go to the Plugin manager in Joomla and look at any plugins in the "jfbcprofiles" group, you should only enable the ones for the components you have installed that you want to integrate JLinked with.
Hopefully, that's all it is. If you're still having issues and have JomSocial installed, just let us know, and we can help you further!
Thanks,
Alex