Problem with missing Browse button in Firefox

Hi, I'm using CK Editor 4.2.1, upgrading isn't easy, so it's not exactly a solution for us.

I have provided a video: http://screencast.com/t/OmaHTzWd1gR which demonstarates the problem.

In Firefox ONLY, when you go to the button to insert an image, the first thing that shows up is the upload section, but in firefox, the 'browse' button is missing, you actually have to close out the diaglog and reopen it to get the button to show back up. I'm not seeing this as an issue in any other browser.

Some help with this issue would be greatly appriciated.