SOLVED No modules are working at all :(

I have a site at: savvyshopperonlinereviews.com.au/?template=beez

I have the login module published and also the fan box.
In the login module, instead of a connect with facebook button 'login with facebook' is just displayed as text and is not a link.
In the fanbox module, I can get the introtext and the powered by link to display but the fanbox itself will not display.

What I've tried

I've run autotune and everything is now showing as ok there
I've (obviously) entered in all the info needed from facebook (app id, page url etc)
All the four plugins needed are activated
I've totally uninstalled and reinstalled the latest versions as of today
I've tried using the beez template that comes with joomla instead of my rockettheme template
I've tried changing the order of the plugins and putting them all first
I've tried unpublished ALL non joomla core plugins I have installed
I've tried placing the sample code {JFBCFan href=http://www.facebook.com/pages/SourceCoast/141717952527296} directly in an article, nothing displays at all
I've set error reporting to max, nothing reported

I had a look at the code with Firebug and the only thing I notice is that while some code is there for the likebox, no CSS is. I'm not sure if this CSS is supposed to come from your extension or from facebook but it's not being loaded for some reason and I thought that could be the problem.

Help please, I've been troubleshooting for hours and am totally out of ideas Happy to provide admin, cpanel and/or ftp logins if needed.

Hi Alex,
Huge thanks for such a quick response

In the language manager I have English set as the default for administrator language packs. English is the only language I use. I don't have any languages listed in the language manager under 'site'.
I tried setting the locale override but it didn't help unfortunately.
I forgot to mention in my initial post that when the website was first built last year it *was* working. It stopped working sometime in the last few months. Not sure when exactly but nothing would have been changed on the site at the time.
Also forgot to mention that my Joomla version is J1.5.26

*CACHE* (Sorry)
It's all working now, thankyou VERY VERY much for your help!