I updated the error messaging so users can see when the link to the forum configuration file is incorrect.
normally the option Forum directory should look like the following.
Forum Directory ../forums/library/config.php
Forum Directory ./forums/library/config.php
I added a new style for the widget.
The style will show the user's avatar in the sidebar widget area.
Fixed a minor issue with PDO Settings.
I added an option to format the table so that it will fit in the sidebar widget.
You can select this option from the WordPress Admin Control Panel.
I added links to the member's names so that it will go the member's profile page.
Additionally I made it so the code base is shared so you can install this widget and the forum stats http://xenforo.com/community/threads/wordpress-display-forum-stats.27508/ widget at the same time.
If you have any questions let me know.
I updated the version to allow for better default values, to help with the installation.