I'm probably going to regret having spent time looking at this dump of the entire website, and it doesn't help that the page is in arabic? (which I don't speak or read)
In pages/header.php you have the following html for lines 41-46:
<li>
<a href="page.html"><span class="l"></span><span class="r"></span><span class="t">ãßÊÈÉ ÇáÝíÏíæ</span></a>
</li>
<li>
<a href="page.html"><span class="l"></span><span class="r"></span><span class="t">ãÚÑÖ ÇáÕæÑ</span></a>
</li>
The anchor tag href is explicitly set to page.html, so when you click on those links, the browser will send a request for page.html in the root folder of the site. This page.html does not exist.
On line 63, you have:
<a href="../index.php#"><span class="l"></span><span class="r"></span><span class="t">ÇáÑÆíÓíÉ</span></a>
change this from ../index.php# to ./index.php#
You seem to have problems with your url paths.