Can't Add Media Elements or edit them via Avia

First off, let me say how THRILLED I am to have found this theme. It’s honest to God revolutionary in terms of ease of use. Seriously.

OK, one small glitch.

I can’t seem to add media elements through the shortcode feature – images, video, etc. – and I also can’t edit buttons or simple image media through the Avia Layout Builder.

When I try to edit these elements, or to add shortcode media, I get the following error message as a pop up –

An error occured

It seems your are no longer logged in. Please reload the page and try again

… this is REALLY an error, as I *am* still logged in, and re loading the page does nothing.

I’ve de activated any plugins I thought might be conflicting, specifically cache plugins, but nothing.

I’ve also contacted Dreamhost (I’m using their upgraded dedicated server hosting, DreamPress), but they tell me it’s a theme related issue.

Any suggestions?