Progress isn't saved? Keeps on deleting everything I do everytime I save and quit.

After having this issue:
Please attach the complete output of the "Development console" which can be found on the second tab of the launcher.

If the launcher closes after game start, please edit your profile and select "Launcher visibility" then, "Keep the launcher open".

Sorry for the inconvinience!

Here is the Development Console:

http://pastebin.com/wuP2g6id

[09:59:46 INFO]: Client> [09:59:46] [Server thread/INFO]: ThePigRider joined the game
[10:00:31 INFO]: Client> s: Saving entity NBT
[10:00:31 INFO]: Client>        at sk.e(SourceFile:1119)
[10:00:31 INFO]: Client>        at sk.d(SourceFile:1086)
[10:00:31 INFO]: Client>        at atc.a(SourceFile:210)
[10:00:31 INFO]: Client>        at atc.a(SourceFile:99)
[10:00:31 INFO]: Client>        at oa.b(SourceFile:161)
[10:00:31 INFO]: Client>        at oa.a(SourceFile:192)
[10:00:31 INFO]: Client>        at ob.a(SourceFile:663)
[10:00:31 INFO]: Client>        at net.minecraft.server.MinecraftServer.a(SourceFile:305)
[10:00:31 INFO]: Client>        at net.minecraft.server.MinecraftServer.u(SourceFile:489)
[10:00:31 INFO]: Client>        at cbx.u(SourceFile:128)
[10:00:31 INFO]: Client>        at net.minecraft.server.MinecraftServer.run(SourceFile:387)
[10:00:31 INFO]: Client>        at mr.run(SourceFile:657)
[10:00:31 INFO]: Client> Caused by: java.lang.NullPointerException
[10:00:31 INFO]: Client>        at aik.j(SourceFile:114)
[10:00:31 INFO]: Client>        at ail.a(SourceFile:125)
[10:00:31 INFO]: Client>        at aai.b(SourceFile:206)
[10:00:31 INFO]: Client>        at sk.e(SourceFile:1107)
[10:00:31 INFO]: Client>        ... 11 more

what was the resolution? Duplicate the save?

On Sat, Feb 15, 2014 at 3:24 AM, [Mod] Kumasasa (JIRA) <[email protected]>wrote:

> [Mod] Kumasasa<https://bugs.mojang.com/secure/ViewProfile.jspa?name=kumasasa>
> resolved an issue as Duplicate Minecraft<https://bugs.mojang.com/browse/MC>/ [image:
> Bug] <https://bugs.mojang.com/browse/MC-48371> MC-48371<https://bugs.mojang.com/browse/MC-48371> Progress
> isn't saved? Keeps on deleting everything I do everytime I save and quit.<https://bugs.mojang.com/browse/MC-48371> Change
> By: [Mod] Kumasasa<https://bugs.mojang.com/secure/ViewProfile.jspa?name=kumasasa> Resolution:
> Duplicate Status: Open Resolved [image: Add Comment]
> <https://bugs.mojang.com/browse/MC-48371#add-comment> Add Comment<https://bugs.mojang.com/browse/MC-48371#add-comment> This message was sent by Atlassian JIRA
> (v6.1.6#6162-sha1:7af547c) [image: Atlassian logo]
>

What ?

what do I have to do? The problem is still there after trying a lot of different methods!