Googlebot getting an error

I have the following code as my index.php for my multi-language website. Each available language has a subdirectory.

<?php


if (isset($_POST['URL']) && strlen($_POST['URL']) == 3) {
         header("location: ".$_POST[URL]);
}
else {

    function lixlpixel_get_env_var($Var)
    {
         if(empty($GLOBALS[$Var]))
         {
             $GLOBALS[$Var]=(!empty($GLOBALS['_SERVER'][$Var]))?
             $GLOBALS['_SERVER'][$Var] : (!empty($GLOBALS['HTTP_SERVER_VARS'][$Var])) ? $GLOBALS['HTTP_SERVER_VARS'][$Var]:'';
         }
    }

    function lixlpixel_detect_lang()
    {
         // Detect HTTP_ACCEPT_LANGUAGE & HTTP_USER_AGENT.
         lixlpixel_get_env_var('HTTP_ACCEPT_LANGUAGE');
         lixlpixel_get_env_var('HTTP_USER_AGENT');

         $_AL=strtolower($GLOBALS['HTTP_ACCEPT_LANGUAGE']);
         $_UA=strtolower($GLOBALS['HTTP_USER_AGENT']);

         // Try to detect Primary language if several languages are accepted.
         foreach($GLOBALS['_LANG'] as $K)
         {
             if(strpos($_AL, $K)===0)
             return $K;
         }

         // Try to detect any language if not yet detected.
         foreach($GLOBALS['_LANG'] as $K)
         {
             if(strpos($_AL, $K)!==false)
             return $K;
         }
         foreach($GLOBALS['_LANG'] as $K)
         {
             if(preg_match("/[[( ]{$K}[;,_-)]/",$_UA))
             return $K;
         }

         // Return default language if language is not yet detected.
         return $GLOBALS['_DLANG'];
    }

    // Define default language.
    $GLOBALS['_DLANG']='en';

    // Define all available languages.
    // WARNING: uncomment all available languages

    $GLOBAL开发者_JAVA百科S['_LANG'] = array(
    'en', // english.
    'es', // spanish.
    'fr', // french.
    );

    /*
    $GLOBALS['_LANG'] = array(
    'af', // afrikaans.
    'ar', // arabic.
    'bg', // bulgarian.
    'ca', // catalan.
    'cs', // czech.
    'da', // danish.
    'de', // german.
    'el', // greek.
    'en', // english.
    'es', // spanish.
    'et', // estonian.
    'fi', // finnish.
    'fr', // french.
    'gl', // galician.
    'he', // hebrew.
    'hi', // hindi.
    'hr', // croatian.
    'hu', // hungarian.
    'id', // indonesian.
    'it', // italian.
    'ja', // japanese.
    'ko', // korean.
    'ka', // georgian.
    'lt', // lithuanian.
    'lv', // latvian.
    'ms', // malay.
    'nl', // dutch.
    'no', // norwegian.
    'pl', // polish.
    'pt', // portuguese.
    'ro', // romanian.
    'ru', // russian.
    'sk', // slovak.
    'sl', // slovenian.
    'sq', // albanian.
    'sr', // serbian.
    'sv', // swedish.
    'th', // thai.
    'tr', // turkish.
    'uk', // ukrainian.
    'zh' // chinese.
    );
    */

    // Redirect to the correct location.


    header('location: /'.lixlpixel_detect_lang());
    //header('location: http://www.your_site.com/index_'.lixlpixel_detect_lang().'.php'); // Example Implementation
    echo 'The Language detected is: '.lixlpixel_detect_lang(); // For Demonstration

}

?>

The problem is that although in user browsers this works perfectly, with search engines (like Googlebot) the following error is thrown:

    <br />
<b>Warning</b>:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Compilation failed: range out of order in character class at offset 12 in <b>/index.php</b> on line <b>41</b><br />
<br />
<b>Warning</b>:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Compilation failed: range out of order in character class at offset 12 in <b>/index.php</b> on line <b>41</b><br />
<br />
<b>Warning</b>:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Compilation failed: range out of order in character class at offset 12 in <b>/index.php</b> on line <b>41</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /index.php:41) in <b>/index.php</b> on line <b>110</b><br />
<br />
<b>Warning</b>:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Compilation failed: range out of order in character class at offset 12 in <b>/index.php</b> on line <b>41</b><br />
<br />
<b>Warning</b>:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Compilation failed: range out of order in character class at offset 12 in <b>/index.php</b> on line <b>41</b><br />
<br />
<b>Warning</b>:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Compilation failed: range out of order in character class at offset 12 in <b>/index.php</b> on line <b>41</b><br />
The Language detected is: en

I have tried error handling but I'm not a PHP programmer, I'm a CF progammer, so I really needs some help!

Inside a character class, the - denotes a range. In this case _-) in [;,_-)] is interpreted as range (every character between _ and ) inclusive). But _ (0x95) is after ) (0x28), so _-) is an invalid range.

If you mean the three individual characters _, -, and ), escape the -:

[;,_\-)]

Apart from that, Accept-Language is a list of weighted values (see the q parameter). That means just the occurrence of a particular language tag does not necessarily mean that it’s the most preferred language. There might be languages that are more preferred (higher q value) or even not accepted at all (i.e. q=0).

So instead of just looking for the occurrence of a particular language tag, you should better parse the list and find the best match of preferred languages and available languages.