What are these Arrows ( ) in the popup for?

The plugin works well for me, except that:
When the page is loaded, the popup loads, but its cntent does not. This is what the visitor sees:
http://imageshack.us/f/819/49410964.jpg/

The popup stays like that, and the content never loads.

But if I click any of the arrows in the bottom of the popup, the shape of the popup changes, and the content loads alright, like this:

http://imageshack.us/f/202/71670458.jpg/

But if the visitor does not do that, the content never loads, and he will eventually close the popup without seeing the content.

What are these arrows for, and why this happens, and what can be done to solve it?

Note: The content is imported from a wordpress Page.
I am generally using W3 total Cache , but I disabled it and still the same. This issue I encounter with all my blogs.