Very simple question

[Imprezer]

When I put $whatever in some template, the $whatever template will show up where $whatever is placed, correct?

How come some templates do not "respond" to $theirname call?

For example, in MyVbindex, I made a custom template and want to call it in the right column by doing $customtemplatename, but it is not showing up.

Why is that?

Also, does it matter if the .php page, in which's template I am placing $customtemplatename resides in / or /forums?

Thanks!