we made a lightning component using liveagent for chat functionality, it was working until spring '17 was deployed. Then liveagent is undefined. Did anyone face similar issue? any solutions?

Trying to design a rich text (lightning component that can be used in community builder) that allows to @mention other users. Is this behaviour available out of the box or if there some reference that I can follow.

There was an error saving the page: The c:componentname component isn't allowed in the main region. The component doesn't implement any of the region's allowed interfaces.

I'm working with Sara Morgan's course on Pluralsight. I noticed I'm hitting this odd error and I'm at a bit of the loss. It appears I can access the app and individual components without any issues and without errors. When i attempt to drag them into app builder, i get the error above  when saving. Has anyone seen this before. I went through and replaced my typed code with hers but I can't seam to find the issue. 

I'm working with her code at this URL: https://github.com/saramorgan/GettingStartedWithLightning/tree/master/M2.  Demo 3 through the last folder: Demo5). You'll need to grab Demo3 thru 5 if you would like to recreate the issue.

I would love to figure out what i'm missing or need to correct to get it to add to the app builder.