Random Logout Issue

[MoB Dudditz MD]

On various pages of my board, mainly custom templates and vBadvanced pages,
I will get a random logout.
In my custom links, I have been using the $vboptions[bburl] in front of urls
to get from upper level content back into the forum.
My Site index is up a level from my forum index.

Should I be using another variable to access forum content such as
$vboptions[homeurl]
or
$vboptions[forumhome].php
?

Do I need to pass any [sessionurl] along with the links?

:example:
My main index page has a link to the archive which is in
MyDomain.com/forum/archive

I have been using $vboptions[bburl]/archive/index.php

Does it really matter?