New Plugin Private Messaging not working in child theme

Hey guys,

I'm just testing your new plugin Private Messaging but it's not working properly on my WP 4.1 install.

In my wp dashboard > messaging > settings, I only see the settings page flashing up and then it's gone; leaving an almost blank settings page.

I've switched off all plugins, reverted back to default theme (child-theme was activated) and Private Messaging worked. It stopped working when I re-activated the child-theme.

Could you make this work for the child-theme?
I've granted you Support Access.

Thank You!