This occurs when I click to add a new post. On Chrome, the error is hidden, and you have to use Developer Tools to see it. On IE, it is a modal popup.
I can confirm that I have this issue as well. If I disable all plugins except WordPress Mobile Pack, I still have the issue. Once I disable WordPress Mobile Pack, the problem goes away. I am running WordPress Mobile Pack 2.0.1 on WordPress 3.9.1.
Thanks,
Ryan
