How to avoid direct access to the forum?

Revenue sharing launched. This is offered as a "thank you" for being a member of webmasterstalks.com community! If you have an Adsense/Yahoo publisher account then you can start right away !

Recover Deleted Files     Php Hosting      Hot Wallpapers     Free Articles     Buy Cheap Ipod

    PDF to Doc Converter     Internet Eraser     Linux web hosting     DoFollow Sites     Movie Reviews

[rucanunes]

Hi,

I've placed this code on index.php of the SMF forum to avoid direct access to the forum:

Code:

// Redirect users who try to access /forum directly
if (strpos($_SERVER['QUERY_STRING'], 'dlattach') === false && strpos($_SERVER['QUERY_STRING'], 'verificationcode') === false)
{
        if(!defined('_VALID_MOS')){ header("Location: http://www.it-info.org/forum/overview.html".$_SERVER['QUERY_STRING']);}}

But than, the Preview Post function stops working. 

Can someone please help me here?

Thank you,
R Nunes