WordPress 2.1

Why is it that when I upgraded to 2.1, all or almost all of my templates don’t work. It keeps saying, “this page cannot be displayed”. For the ones that work that page will pop up and I have to continuously refresh it in order for it to work.

Also, when I download a new template and upload it to wordpress most of them don’t show all the cool effects and designs that it shows on the test site?