Columns button not working in Dental theme

Hi,
I am trying to format a page on my website and want to add columns. When I try to press the columns button, an error message comes up.

The error message is:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.

Am I doing something wrong?

Thanks so much for your help!

Hi!

You need more information about this error to find a solution. To get it you should enable debugging in WordPress, using this instructions http://codex.wordpress.org/Debugging_in_WordPress. Then try to add columns again and see what the server will say. If you will see only "Internal Server Error" and no description, you should contact your server administrator or hoster and ask them to send you error message from the logs.