Demaestro - 8:25 pm on Dec 10, 2009 (gmt 0)

If you have Firebug installed as an add-on then you can see if the request is being made.

All you have to do is activate the "console" part of Firebug and reload the page. Any Ajax requests will be shown there.

It may offer more clues, like if you see a request and an response but nothing loading on the page then at least you know that the requests are happening.

I am using the latest install of Ubuntu's FF and have had no issues.