<span>Table 'e10720180621.e107_private_msg' doesn't exist</span>
I checked menu, pm section, admin... there is set class nobody if this this plugin is not installed.
And if you have no permission, this section is not displayed.
Everything looked correct...
and there I saw it, stupid mistypo in original plugin, not installed plugins had wrong numbering
Just playing with google custom search. It's searching this site, e107.org and github with e107 in repository name.
If you use any my theme: with version 2.2.0 there are core changes - comments and social icons - if you find problem, just tell me.
I will be on holiday until end of November. So no answers from me until then.