I have a website hosted on a dedicated server, I noticed that Google and other search engines can't access to the most URLs on my website!!

On my localhost I have made a small test :

var_dump(fopen('http://www.aswat.ma', 'r'));

And I got this error :

Warning: fopen(http://www.aswat.ma) [function.fopen]: failed to open stream: HTTP request failed! HTTP/1.1 500 Internal Server Error in C:\xampp\htdocs\pnowate\public\index.php on line 4 bool(false)

If I change the URL "http://www.aswat.ma" by "www.google.co.ma" I got this :

resource(3) of type (stream)

Any one have any idea about this issue ??