[Makc666]

1.
Did you applied this patch?
https://vborg.vbsupport.ru/showthread.php?p=1788517
If no, do it and re-upload the product.

2.
Have you change vBulletin's version in ACP in Debug mode?
In other words do you see version 3.7.1 on forums?

3.
There is no such function as "function fetch_require_hvcheck" in vBulletin version 3.7.1
There is a special check for this one in version 2.0.1 of this mode.

Here it is:

PHP Code:

            // fixed 2.0.1 unknown function in vB 3.7.x.
            if($vMail->vB_version(8) AND (function_exists('fetch_require_hvcheck') && fetch_require_hvcheck('register'))) {
                // vBulletin 3.8
                require_once(DIR . '/includes/class_humanverify.php');
                $verify =& vB_HumanVerify::fetch_library($vbulletin);
                $human_verify = $verify->output_token();
            } 


It looks like some problem on your side.