[Tigga]

Netstartz - Nice site. To add more custom templates, please check this post. The instructions there should be pretty simple... Then to have it so they can be turned off and on in your Admin CP, please see this post for the queries you would need to run.

refertech - Changing the image that way won't affect anything unless you have multiple styles for your board. If you do and a user selects a style besides the default, then they will see the wrong icon there. Other than that though there's nothing wrong with changing that.
You are right about the custom templates being switched... Well, actually it does display the correct template, but the index_custom1 template has "Custom 2" in it and vice versa. I'll be sure to update that in the next version so thanks for pointing that out.
What do you have set for the URL under "General Settings" in your main vBulletin options? I would suggest making sure that is set to the full URL to your forums as it seems that none of your links in the header work either... Those links and the login form use that option to determine what the URL is, so you should check to make sure it's set correctly.