I have tried this out here and it seems to work fine for me. However, looking at the code, I can see one possible cause (although it shouldn't really be happening). If you send me an email at
support@gabysoft.com, I can make a change and give you a version that you can try to see if it fixes the problem.
One thing I would like you to try, however. If you reboot your phone, does the 'upload' button work again (at least one time)?