500 internal error & another gallery has an internal error with additional 404
we have been a client for a long time and have purchased a number of your products but at this point we are having an issue with a gallery on a site www.imagesbygb.com this is the one with internal error as seen here index.php?gallery=1&theme=light
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, webmaster@imagesbygb.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 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
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Apache/2.2.22 (Unix) mod_ssl/2.2.22 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at www.imagesbygb.com Port 80.
hope you can shed some light