Misleading errors

I recently started seeing the attached error warnings on my multisite's new user/site sign up, and have traced it down to this plugin. I'm not sure whether there's a chance that something else is conflicting with this plugin, but I can't think of anything that I've done that would have caused any issue here (no new plugins, and no changes to the theme in question on my primary site).

I have confirmed that the warnings aren't actually preventing the site from being created. I can't see anything wrong with the registration other than these warnings are misleading, and I know that they are causing people to exit the site after what would have been a successful conversion (registration), which now I have to try to salvage.

I loved this plugin, but it's no longer usable. I'd appreciate prompt support. Thanks.