Issue with vBulletin php include on non vb page

[DandD]

We have a new site on which we use a php include to display calendar.php on the home page. It seems to work well with two exceptions. Fist, we noticed the calendar view links are not in the proper place and second, the user login status is incorrect (user is not shown as logged in when he is). These problems are on the home page (root folder - index.php), but the calendar.php page in the forum folder works correctly.

The site home page is: www.lahabraevents.com
The calendar page is: www.lahabraevents.com/forum/calendar.php

We suspect the problem is a sessions issue due to the home page being in the root folder rather than the forum folder, but we need help from someone a little more knowledgable. Any help is appreciated.