[Arjan]

True word.... I noticed

And the'' be kind show the user what is wrong' is also not a good idea.
Updating the errorstring and showing the form again invites the spammer (spambot) to retry. My server got huge pageloads in the last couple of hours (5 times more) with a normal, even a bit low, amount of visitors. Which resulted in an overloaded CPU.

I saw I forgot two pieces of code. And with the just Die version you will get this for the second part:

    //ANTI SPAM PART 2
    // Allow only the sendmessage script 
    $MyReferrer = strtolower($_SERVER['HTTP_REFERER']); 
    $MyURL = strtolower($vboptions['bburl'] . '/' . $vboptions['contactuslink']); 
    if($MyReferrer != $MyURL) 
    {  
		//eval('$errors[] = "' . $AntiSpamMessage1 . '";');
        die($AntiSpamMessage); 
    }  

    // Filter header injections
    $MyHeaders = array(
        "content-type:", 
        "mime-version:", 
        "content-transfer-encoding:", 
        "bcc:", 
        "cc:"
        );


    // Check for the number of hrefs in settings.
    // This makes it pretty secure against future spam versions.
    $MyPostItem = strtolower($_POST['message']);
    $MyTempItem = explode('href=', $MyPostItem);
    if(count($MyTempItem) >= 2)
    {
        die($AntiSpamMessage);
    }


    // Loop through each POST item and check for the headers
    foreach($_POST as $MyKey => $MyPostItem)
    {
        $MyTempItem = strtolower($MyPostItem);
        foreach($MyHeaders as $MyHeader)
        {
            if(strpos($MyTempItem, $MyHeader) !== FALSE)
            {
                die($AntiSpamMessage);
            }
        }
    }
	
    // Check for strings in the message body. 
    // This string is found in automated browsers (all yet) at the bottom. 
    // For completeness we parse all post variables for this string. 
    // Prepared for more recognition strings. 
    $MyStrings = array( 
        '9c53d2119880d95e96e1a71e3a6c8340',              // the start
        'dc64615b0a1e1bd3cb2689bf82248b5c',              // 2006-06-27
        'f4dd026ac39b9e2fa576404ae93f215c',              // 2006-06-30
        '849b90dee61199d2ed871b18e1575cb5',              // 2006-07-06
        '05980283d7fb0e8cc54b17a2b2a0ab96',              // 2006-07-10
        '70fcdb09b8b18b50874603a6c99fcbcb',              // 2006-07-15
        'bd0e28eaccfa349da99ddd3880835725',              // 2006-07-16
        '71b0d16f90c6ef289fb9e0b08b44fd7c',              // 2006-07-16
        'df487ef8b49cead02c1a5d00a04288ce',              // 2006-07-21
        '6d02afe3993f73507d90e3f877d8eed8',              // 2006-07-23
        '5064a72d6d1acabba6a21f655481a5b5',              // 2006-07-24
        '33766d282efd27c3468309e546e247c5',              // 2006-07-29
        'c9551bfed82d85381e7fd1deb6fef0af'               // 2006-07-30
        ); 

    // Loop through each POST item and check for the headers 
    foreach($_POST as $MyKey => $MyPostItem) 
    { 
        $MyTempItem = strtolower($MyPostItem); 
        foreach($MyStrings as $MyString) 
        { 
            if(strpos($MyTempItem, strtolower($MyString)) !== FALSE) 
            { 
		      //eval('$errors[] = "' . $AntiSpamMessage2 . '";');
              die($AntiSpamMessage); 
            } 
        } 
    } 

    // Cleanup 
    unset($AntiSpamMessage, $MyReferrer, $MyURL, $MyHeaders, $MyKey, $MyPostItem, $MyTempItem, $MyHeader, $MyStrings, $MyString); 
	
    //END ANTI SPAM PART 2