Pligg Support

I want to add extra comment field. I have tried as following:

1. Created extra column "extra_comment_field" into "pligg_comments" table

2. Added following code to comment_form.tpl
input type="text" name="extra_comment_field" id="extra_comment_field" 

3. Added following lines into comment.php

$extra_comment_field= $db->escape($this->extra_comment_field);

And changed following line:

 $sql = "INSERT IGNORE INTO " . table_comments . " (comment_parent, comment_user_id, comment_link_id, comment_karma, comment_date, comment_randkey, comment_content, extra_comment_field, comment_status) VALUES ($comment_parent, $comment_author, $comment_link, $comment_karma, FROM_UNIXTIME($comment_date), $comment_randkey, '$comment_content', '$extra_comment_field', '$comment_status')";

But it is not writing data to db column ? What am I doing wrong, please help me. I am new to php and pligg.
how the module pass info about where to place a 'log in with facebook' button to e.g pligg.tpl login modal. I changed my template a little, and want to place the button in different order than comes with the module.
And something weird happened: I connected an existing admin profile with fb account and later disconnected my pligg account from fb (using btn in settings tab). After this I had to reset my password (I know that probably you don't store old password after connecting with fb but then the option for disconnecting is not good cause it leads to problems and additional steps you need to do to further use your account.) - just a thought

Thanks for reply
I've configured the module but it doesn't appear to be working.
Hi all.. does any one know how to making so will automatic generate tag during submiting..

I have a problem with my pligg cms, I came over me connect to my admin account does with another user account.

What is the problem?

Can you help me?