Corrupt-Causes MIDI sharing bug
I finally decided to go through my apps one by one and delete them, and try to identify the culprit. Well, guess what, I found the culprit, and it is MIDI Keyboard!
I deleted it, and now, I can finally share midi files again. This was a nightmare. If you have midi files in dropbox or a AudioShare or FileBrowser, and you want to use them on your iPad DO NOT download this app.