Is vB5 Connect suppose to replace vB4?

[Kwak]

Info: vB4 forum was installed on the home/root directory. Installed vB5 Connect on a new directory named /content/

Installation and upgrade process completed. The forum is now showing up under /content and getting the following error message on the home URL

Warning: Invalid argument supplied for foreach() in [path]/includes/functions_navigation.php on line 355

Fatal error: Call to undefined method vB_Template_Runtime::vBVar() in /home/name/public_html/url/includes/class_core.php(4716) : eval()'d code on line 71

Plan was to have vB5 upgrade the vB4 installed on the home/root directory (e.g. www.vbulletin.com) but the installation told me to create a new directory for vB5.
Anyone know what is causing that error? Thanks.

[Wayne Luke]

It is meant to be an upgrade. You'll need to uninstall any addons or template customizations first. The system is completely different.

[Kwak]

How do you make the forum show up on the home url (forum directory) instead of the new directory (vb5 installed on) where the forum is now showing up at?

I can't uninstall the customized template on admincp due to database errors. Removed addon: Impex