Filling in all the boxes before something will upload... text size important when viewing page!
On my laptop when the box pops up to fill in the details it can't be scrolled down (I'm using IE) although it can on my iPod. Some folk, depending on their settings will not be able to see the boxes further down the page, that need to be filled in, unless they make the size of the text smaller. Maybe this is something that you'll need to flag up to users... I didn't realise for ages and kept going over the same thing and wondering why it didn't happen when I tried to upload my images.