500 Service Error

Hello,
I have just created a new wordpress website and am receiving an error every time I attempt to access any page but the home page. The URL is http://www.chriscartoons.co.uk –

“Internal Server Error

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

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

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.”

I don’t recall doing anything to cause this, as I’ve only had it up and running for about an hour and have only created pages, changed the Tagline, and added background and header images. It is hosted on a Justhost account. Can anyone help me with this? How do I fix it?

Thanks in advance!
Robyn