The "Select File" button does not work for me on Firefox 15.0.1 / OSX 10.8.2 while it does when I use Chrome, bug or deliberate choice?
The other thing that is rather confusing is that having selected the file, it's not clear how to proceed. I eventually clicked 'What have I missed' which seems to actually be 'I've not missed anything please click this button' - I think this could be better worded to just 'Go' or something similar once the file is selected.