WP Code is not writing to MySQL

I was trying to add some more features to one of my WP codes. So I created few columns under “wp_usermeta” and modified my php code as follows:

• <h2><?php echo __(‘Linkedin Profile’,’MyTheme’); ?>:</h2>
  <p><input type=”text” size=”35″ value=”<?php echo get_user_meta($uid,’user_linkedin_url’,true); ?>” name=”user_linkedin_url” class=”do_input” /></p>

So under “wp_usermeta” I created a row, and entered “user_linkedin_url” for meta_key and left everything else blank. When I manually enter a value (i.e. to meta_value) the site is able to pull that info, but it is not letting my write anything to the database.

Not sure what I am doing wrong