Including global.php on other pages, caching issue!

[Swedie]

Hey! I've recently upgraded to vB4, everything works sorta OK, except for the caching of the main page on the site (and probably other pages).

The first page has a list of latest threads. I can go to one of these threads and post a message, and browse back to the start page and my post won't show up, not until I have refreshed the page again.

Site: www.sporthoj.com
Forum: www.sporthoj.com/forum

The code basics:
There's a header and a footer file. The header includes the vB global.php file so I gain access to the super object $vbulletin and know whether a user is logged in and so forth.

The forum includes my header and footer (through plugin, bootstrap_init) to wrap the forum with the site theme.

Outside of the forum I use standard php for doing mysql queries, meaning: mysql_query() commands. I am not going through vB's object $vb->db...

I've turned off caching completely in the vB settings. This had no effect.

Are there other things in vB4 that can cause PHP to do (for me) unwanted caching of the PHP pages?