Facebook widget code messing up the page

[ComoEstaEso-com]

Hello everyone,

Everything was running fine on my forum.
I decided to add a facebook widget with the latest posts to a certain layout.
When I did this, various "code" lines appear on the top of the page... and then the page loads fine.
Below a screen shot of the facebook widget inserted into this layout, on the right.
You can see the "code" lines on top.
Attachment 143846

To fix, I have to remove the facebook widget, clear the system cache vB CP --> Maintenance --> Clear System Cache
Then reload the page.

After that is done, all is good.
Below a screenshot of the page with everything working as it should.
Attachment 143847


The odd thing is, that his happens only on a page where I'm running a javascript.
I have been running the facebook widget in question in the same forum, yet in pages with a different layout, and without the javascript.
It works fine.

I don't know if it's the javascript that's messing up the code, or what.

Here's part of the "code" that's coming up:

Warning: unserialize() [function.unserialize]: Function spl_autoload_call() hasn't defined the class it was called for in [path]/vb/cache/db.php on line 151

Warning: unserialize() [function.unserialize]: Function spl_autoload_call() hasn't defined the class it was called for in [path]/vb/cache/db.php on line 151

Warning: unserialize() [function.unserialize]: Function spl_autoload_call() hasn't defined the class it was called for in [path]/vb/cache/db.php on line 151

Warning: unserialize() [function.unserialize]: Function spl_autoload_call() hasn't defined the class it was called for in [path]/vb/cache/db.php on line 151

Any thoughts on what I can do to fix this?
What could I check to try and narrow down the error?

Thank you very much!