recaptcha return empty page on mediawiki

Hi all, from Argentina, i'm sorry in advance about my poor english, my language is spanish :-)I need captcha on mediawiki, for prevent or minimice spams and bots.I use MediaWiki 1.19.3.I found recaptcha, by google and suggestions ican found.I follow all steps on https://developers.google.com/recaptcha/docs/mediawiki?hl=es&csw=1I copy recaptcha uncompressed folder on extensions folder.I change LocalSettings.php.I try check and changes, by try and error. All cases, i receive empty pages when active this line:require_once( "$IP/extensions/recaptcha/ReCaptcha.php" );and no recaptcha when mark it as:# require_once( "$IP/extensions/recaptcha/ReCaptcha.php" );i try it on 2 working wikis, one in use and other for testing.What or where i'm mistake or error? What i can check or change for this wikis work?I expect you can understand and help me. Tks in advance. Best regards :-) -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://groups.google.com/group/recaptcha. For more options, visit https://groups.google.com/groups/opt_out.