The inputFile component is not working with FF 3.0.7.
The main cause is that the "action" attribute of the upload form is being set to web context based URI. Changing the URI to fully specify URL fixes the problem.
After debugging it came across that FF made some intentional changes (for security purpose) or a regression that if you create dynamic contents to the iframe, then any form inside must use fully specify URL to the form action
The following demos demostrate the issue with FF 3.0.7

• This demo uses upload component markup in the page, it works fine
• This demo uses upload component inside an html file which is being add to another file using the ifram src, it works fine
• This demo generats upload contents dynamically to the ifram, it does not work