PHPnuke 6.9 Access Denied

[talal]

I have installed nuke 6.9 and created the database. After that I created the admin username and password and logged in with no props to the Administration Menu, everything looks ok put when I try to click any of the administration sections such as edit users... Admins...Etc
a message : Access Denied would appear and I can not access it ..
so I checked nuke_authors table in the Database and radminsuper =1

so i thought mybe the files and the database needs to be reinstalled.... that didn’t work to

so I removed the security code in the header of one of the admin modules files so just I can check if I do that I would access it or not
so this is what I removed :

if (!eregi("admin.php", $_SERVER['PHP_SELF'])) { die ("Access Denied"); }

$result = sql_query("select radminuser, radminsuper from ".$prefix."_authors where aid='$aid'", $dbi);
list($radminuser, $radminsuper) = sql_fetch_row($result, $dbi);
if (($radminuser==1) OR ($radminsuper==1)) {

and from the footer

} else {
    echo "Access Denied";
}

after that I deleted all of the 6.9 files and directories and installed 6.5 .. the same problem again .. so I thought maybe its from the FTP so I changed the software 3 times my last ftp software is CuteFtp pro
This problem happened to me on my other site, I had a working version of nuke 6.5 and when I tried to update it I had the same problem


Did any one had the same problem or can anyone help me please??