“headers already sent” messages, problems with syndication feeds

We had installed the latest stable version of this extension in our WordPress installation. But on the server we are getting following notifications so we thought of sharing with you-

1. Error Notification-
The plugin generated 224 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.

2. Warning-

“Warning: symlink() has been disabled for security reasons in ../wp-content/plugins/ultimate-ads-manager/admin/class-ultimate-ads-manager-admin.php on line 1092”

Kindly, review the code & update the latest version of extension in order to address the above errors.

Thanks.