500 internal server error

Hi
i am running easy fancy box version 1.5.0 and it is not working on my site
by analyzing the page with the inspection tool of chrome i get

Failed to load resource: the server responded with a status of 500 (Internal Server Error)

i then analyzed the server logs and i get:

[Thu Jun 13 12:20:42 2013] [error] [client 79.171.164.132:34424] – http://www.noiduepercaso.com – End of script output before headers: easy-fancybox.css.php, referer http://www.noiduepercaso.com/
[Thu Jun 13 12:20:42 2013] [error] [client 79.171.164.132:34424] – http://www.noiduepercaso.com – AH01215: suexec policy violation: see suexec log for more details, referer http://www.noiduepercaso.com/
[Thu Jun 13 12:20:41 2013] [error] [client 79.171.164.132:34424] – http://www.noiduepercaso.com – AH00687: Negotiation: discovered file(s) matching request: /web/htdocs/www.noiduepercaso.com/home/index.htm (None could be negotiated).

Can anyone help?
The site is located at http://www.noiduepercaso.com

thanks!

http://ww.wp.xz.cn/extend/plugins/easy-fancybox/