after vbhome , how do i change the global home?

after installing vbHome , I had to move my default forum index.php down a level in the directories ... so it used to be root , but is now /root - how can i change the global board URL safely , so that when users log in , or are taken back to the main forum index , they are instead taken to my new vbhome index.php?

i just can't seem to find the global variable for the URL of the board?