Games : Why are my minecraft files not up to date? [on hold]

I'm having a similar problem mentioned in this question.

My confusion is I haven't changed ANYTHING in my files, I haven't played in quiet some time for sure, but this all worked a few months back when I last played.... I had a FTB Test Pack Please Ignore server, and I would run it on my PC, then login and play with friends and family. Now my server wont start giving me an error message quite similar to the one in the linked question. Why would my local files be suddenly out of date?

Here is a Pastebin to my crash log.