Krångel med php

Det är något konstigt med ett av mina script. Först fungerar det och sedan inte sen efter ett tag fungerar det igen. någon som kan förklara? här är det:

<?php

if (is_user($user)) {

require_once("mainfile.php");
get_lang("Games");

function menuimg($gfile) {
    $ThemeSel = get_theme();
    if (file_exists("themes/$ThemeSel/images/menu/$gfile")) {
	$menuimg = "themes/$ThemeSel/images/menu/$gfile";
    } else {
	$menuimg = "modules/Games/images/$gfile";
    }
    return($menuimg);
}

function nav($main_up=0) {
    global $module_name;
    $handle=opendir('themes');
    while ($file = readdir($handle)) {
	if ( (!ereg("[.]",$file)) ) {
		$thmcount++;
	}
    }
    closedir($handle);
    echo "<table border=\"0\" width=\"100%\" align=\"center\"><tr><td width=\"10%\">";

    $menuimg = menuimg("gamelinks.gif");
    echo "<font class=\"content\">"
	."<center><a href=\"modules.php?name=Games&amp;op=1\"><img src=\"$menuimg\" border=\"0\" alt=\""._GAMECHEATS."\"
title=\""._GAMECHEATS."\"></a><br>"
	."<a href=\"modules.php?name=Games&amp;op=1\">"._GAMECHEATS."</a>"
	."</center></font></td>";

    $menuimg = menuimg("downloads.gif");
    echo "<td width=\"10%\"><font class=\"content\">"
	."<center><a href=\"modules.php?name=Games&amp;op=2\"><img src=\"$menuimg\" border=\"0\" alt=\""._GAMEDOWNLOAD."\"
title=\""._GAMEDOWNLOAD."\"></a><br>"
	."<a href=\"modules.php?name=Downloads&amp;d_op=viewdownload&amp;cid=2\">"._GAMEDOWNLOAD."</a>"
	."</center></form></font></td>";

    $menuimg = menuimg("minigames.gif");
    echo "<td width=\"10%\"><font class=\"content\">"
	."<center><a href=\"modules.php?name=Games&amp;op=3\"><img src=\"$menuimg\" border=\"0\"
alt=\""._GAMEREVIEWSNEWS."\" title=\""._GAMEREVIEWSNEWS."\"></a><br>"
	."<a href=\"modules.php?name=Games&amp;op=3\">"._GAMEREVIEWSNEWS."</a>"
	."</center></form></font></td>";
	
    $menuimg = menuimg("cs.gif");
    echo "<td width=\"10%\"><font class=\"content\">"
	."<center><a href=\"modules.php?name=Games&amp;op=4\"><img src=\"$menuimg\" border=\"0\" alt=\"CS Serverstatus\"
title=\"CS Serverstatus\"></a><br>"
	."<a href=\"modules.php?name=Games&amp;op=4\">CS Serverstatus</a>"
	."</center></form></font></td>";

    echo "</td></tr></table>";
    if ($main_up != 1) {
	echo "<br><center>[ <a href=\"modules.php?name=Games\">"._RETURNGAMES."</a> ]</center>\n";
    }
}

}

if (!eregi("modules.php", $PHP_SELF)) {
	die ("You can't access this file directly...");
}

$module_name = basename(dirname(__FILE__));
get_lang($module_name);

$ThemeSel = get_theme();
#include("themes/$ThemeSel/theme.php");
include("header.php");
$headerdeclared = 1;

OpenTable();

if ($op != "") {
	nav(2);
	CloseTable();
	echo "<br>";
	if ($op == 1) {
		$l_op = "viewlink";
		$cid = 4;
		include("modules/Web_Links/index.php");
	} elseif ($op == 2) {
		$d_op = "viewdownload";
		$cid = 2;
		include("modules/Downloads/index.php");
	} elseif ($op == 3) {
		$new_topic = 4;
		include("modules/News/index.php");
	}
} else {
	echo "<center><font class=\"option\">"._GAMESTITLE."</font><br><br>"
	    ."<font class=\"content\">"._GAMESDESC."</font></center><br><br>\n";
	nav(1);
	CloseTable();
}

$index = 1;

include("footer.php");
?>