php 文件第一次加载404，刷新就可以了？？

ie下，第一次加载 404错误ff下，一切正常？？这是测试地址http://202.108.152.203:8080/tmp/SSOTest/testURL.php服务器跑的apache
<?php
include_once('GTHCAS.inc.php');
include_once('CAS.php');
phpCAS::client(CAS_VERSION_2_0,GHT_SSO_SERVER,GHT_SSO_PORT,GHT_SSO_PROJECT);
phpCAS::setNoCasServerValidation();if(phpCAS::checkAuthentication())
{ $uname = phpCAS::getUser();
echo $uname;
if(!empty($uname))
{
echo "<a href='logSSO.php?action=logOutSSO&redirectService=".$_SERVER['REQUEST_URI']."'>退出</a>";
}
}
else
{
echo "&nbsp;&nbsp;&nbsp;&nbsp;<a href='logSSO.php?action=login&redirectService=".$_SERVER['REQUEST_URI']."'>登录</a>&nbsp;&nbsp;&nbsp;&nbsp;";echo <<<EOB
<iframe scrolling="yes" width="300" src="http://sso.gotohui.com/sso/loginEmbed?service=http://localhost/SSOTest/testURL.php">
</iframe>
EOB;
}
?>