jQuery - Plugins not working in loaded content

jQuery - Plugins not working in loaded content

Short version:
 
I load content from a separate php page into a div in my other page. This is done using .Get I believe.
I've taken the plugin from net tuts +
 
This is working, however, plugins that are supposed to work with the content that's just arrived aren't.
Only when specifying that page and loading that as a whole.
 
Long version:

I'm doing a website that's pretty graphics intensive. It's more like an application really, only with very "scarse" interface. So I liked the idea of loading only the new content directly onto the already loaded page instead of reloading everything.

And so I found a plugin from net tuts that did the very same thing.
http://nettuts.s3.cdn.plus.org/011_jQuerySite/sample/index.htm

Basically, this plugin lets you load content from a said div container directly as a feed onto the page that's already loaded. So all pages are the same, with the only change being in the same div container as all pages have.

Now, several issues occurred. What I find strange(probably not for you) is the fact that plugins that I use somehow stop working when loading the content using the said plugin.
Cufon stopped working on the newly arrived content. And the same thing happens with a slide menu plugin as well that also arrives with the new content. But if I completely load the page that contains the div with Cufon and the slide menu, everything works as normal. But as soon as I click a link and new content arrives, plugins in that content does not work.

What am I missing? The pages are completely identical, with only a few differences in the a div container that both pages have. Clicking links are supposed to only remove existing content, fetch new content and place it in exactly the same location. One would think that scripts that are already loading in <head> would work with the newly arrived content as well?