Question

require_once('/recaptcha/recaptchalib.php'); was in the correct place 

but the error says:

Warning: require_once() [function.require-once]: open_basedir restriction in effect. File(C:\/recaptcha/recaptchalib.php) is not within the allowed path(s): (C:\Inetpub\vhosts\xxx.com\httpdocs\) in C:\Inetpub\vhosts\xxx.com\httpdocs\wp-content\themes\xxx\download.php on line 5

Line 5 point to require_once. I am not sure why it gave error, when on local development it doesn’t complain.

EDIT #2
Warning: touch() [function.touch]: Unable to create file C:\Inetpub\vhosts\xxx.com\httpdocs/csv/brochure-list.csv because No such file or directory in C:\Inetpub\vhosts\xxx.com\httpdocs\wp-content\themes\mta2013\downbrochure.php on line 161

code:

$filename= ABSPATH. 'csv/list.csv';
            $isNew = (file_exists($filename) || is_file($filename)) ? false : true ;
            touch($filename); //Sets access and modification time of file and  If the file does not exist, Create it.
            $fp = fopen($filename, 'a+');
            forceHeader($columns,$filename);

            fputcsv($fp, $formData);
            fclose($fp);

I might be overlooking something here. but I added ABSPATH and it doesn’t resolve the error.

EDIT #3

Alright I resolved it because the directory wasn’t set to permission or ‘recognized’. thanks for the help.

Answer 1

By using

require_once('/recaptcha/recaptchalib.php');

You are actually directing PHP to the root folder(which in windows is C:\) while you actually want to move to the following folder:

C:\Inetpub\vhosts\xxx.com\httpdocs\

I guessed that your server folder is httpdocs, and PHP by-default takes it as its base directory. Hence, you don’t need to use the /recaptcha. Therefore,

require_once('recaptcha/recaptchalib.php');

Works great.