You did update your concrete5 to 5.6 right? But why is the update folder still in your main? Could you clarify that? Try to clear your cache, and if you updated it to 5.6, try to delete your update map. Make a back-up though..

When upgrading, I can't remember the reason why, but I updated manually following the procedure listed here:http://www.concrete5.org/documentation/how-tos/developers/manually-...

Cache has been cleared over and over and I've tried almost all cache options in different combinations.

I assume that u used the first method. And I don't now why, but I guess (so I could be totally wrong) that's when your site is using the 'new' core, something (references) is going wrong. "Note: The end result is that your site's old core still resides in concrete/, but we've added a new line to config/site.php that tells the site to essentially ignore it, and use the new core in the updates/ directory instead. Here's what that line might look like:"
Could you check your site.php and look if something is out of the ordinary?

Yes, there is this line:

Sounds right though... Did you also took a look at this?

"Core version vs. database schema version"

http://www.concrete5.org/documentation/how-tos/developers/troublesh...

Hmmm interesting. I won't have time until Monday, but perhaps I'll try running the upgrade script again just in case my database is old version

Prettify.js is a source code prettifier by google. Sunburst.css is a theme for it.

Have you been using a code highlighting addon? The files are in quite wide use amongst code highlighters, development systems and also on major sites like stackoverflow. So maybe you had some third party diagnostic tool in use at some point of your development and there are remnants of it still clinging to the site?

These libraries are one option in my Syntax Anywhere addon. I don't have you listed as a user so they will almost certainly have come from elsewhere.

Don't have a code highlighting add-on.. But I've had to update ProBlog multiple times and I feel that maybe it's related to that add on.

I'm going to get in touch with ChatStrat to see what he thinks...

Make sure you are on the latest PB. I did mistakenly push 1 version without those, but quickly added them back. That was a mistake.

ChadStrat