I looked into your file and it appears you may have accidentally deleted your character. This is very easily done by an accidental pressing of 'x' followed by a left-click. This has happened to me many times. My recommendation is that you try undoing the change. Your trouble with armature may be due to the fact that the automatic weight painting did not work and you need to weight paint each bone individually. Hope this helps.
Just a note for next time: please post a direct copy of your .blend file rather than a dropbox link. Thank you.