Try reinstalling, the database tables were not created during install. I have had to add the tables to the database on many addon for many that have this same problem on a few addons.

I reinstalled and same database problem.

Login to your cpanel, then phpMyAdmin, click on the database that goes to your site.
Look down the list on the left, look for invitation, from the error you are show, you will not see it.
Also, via phpMyAdmin, create a backup of your database before you edit it, you can create the backup through phpMyAdmin & it will be stored there as well. That way you have a copy if you mess up.

I added the sql table you need that is missing, thus causing the database error.
Just import it into your database.
You should be good to go.

Thanks Eddie your a great help... Worked fine.

i have installed this but i am facing this error on the top of navbar

I am getting the same too

Could we get 4.2 update?

thank you so much..

can we have for vb 4.2.x ???

Same Problem here. When i go in to the UserCP and then navigate to the invites, it shows me up the following error on the top of the site:
greez