ReCAPTCHA library - ignited

[eluser]kaluzhanin[/eluser]
This is a great library. But is it server-configuration dependent?

The problem is, I had to move to another platform (from ubuntu-LAMP to windows-XAMPP), and recaptcha never validates now.

Here's the excerpt from debug log:

Code:

DEBUG - 2010-04-16 21:20:23 --> Recaptcha::_qsencode(
Array
(
    [privatekey] => <valid value>
    [remoteip] => 127.0.0.1
    [challenge] => <long and obviously valid sequence of characters>
    [response] => height polecats
)

)
DEBUG - 2010-04-16 21:20:23 --&gt; Recaptcha::_http_post response:Array
(
    [0] => HTTP/1.0 200 OK
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Pragma: no-cache
Expires: Fri, 01 Jan 1990 00:00:00 GMT
Date: Fri, 16 Apr 2010 17:20:28 GMT
Content-Type: text/plain
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
Server: GSE
    [1] => false
'Input error: response: Required field must not be blank\nchallenge: Required field must not be blank\n'
)

So, as far as I understand, user response doesn't get to recaptcha.net. Why is that?

Any advice would be much appreciated.