500 internal server error-paypal and google problem

[devilstoybox]

I somehow fixed the 404 error problem. Now i can get through to the end of the checkout but when i select paypal i get:
"Internal Server Error

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

Please contact the server administrator, [email protected] 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 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."

and when i select google:
"Oops!
Devil's Toybox has sent Google a shopping cart with errors in it. We'll contact them to ask that they fix this problem. As this could be a temporary issue, you can go back in your browser to try checking out again.
Debugging information

If you are acting on behalf of the merchant, more information about this error has been made available in the Integration Console under the Tools section. You can access the details of this error directly by logging into your merchant account and then pasting the following url:
(gives url)

how do i fix?

[Robert G.]

Fix the permissions on your files; this is a recurring installation issue.
See also: http://www.presto-changeo.com/content/13-fixing-error-500