Problem with redirect 301

Hi
i have created an redirect 301 from one link to another, i have write the code to do this in the .htaccess file and i have tried with a plugin.
I have redirect the link http://www.guadagnareconblog.com/come-installare-wordpress/ to http://www.guadagnareconblog.com/installare-wordpress-in-locale-con-xampp/
I have used this code in the .htaccess file: redirect 301 /come-installare-wordpress/ http://www.guadagnareconblog.com/installare-wordpress-in-locale-con-xampp/
But when i open the link, exit an error because the link the appears is http//www.guadagnareconblog.com/installare-wordpress-in-locale-con-xampp/ (without 2 points).
How i can resolve this problem?
P.S.: In the .htaccess file i have wrote http:// instead of http//