When I tried starting a world that I had played a while ago I got that error/crash.

Aparently there are some EntityManaBursts at invalid locations how ever they got there, ithere a way to fix that or similar?

As soon as the backup starts I find myself back to the main menu. I can go in to the options, the mods screen but if I either try to start another world or quit minercaft itself it stops responding. I can only guess that the client is somehow not able to deal with the EntityManaBursts at invalid locations... I really don't know if you can replicate that... But, maybe...??
There is no real crash report so latest client log: http://pastebin.com/JxGTaZXj.

Seems like world corruption caused by something else. With no leads I can't tell what causes it.