I just found another crashlog that almost matched the one i got. Will test further, it seems to be a problem with the taint biome.1. may. Unstable 1.0.3. Had been playing for a while on this world, when suddenly it crashed and deleted my character save, i spawned back in the world with no items except the book from tinkerer, and then it started crashing every 1 minute in game. I have tried some different things to fix this, updated java to version 60 (crashlog is with updated java, but it startet happening on the last version).
Another bug i noticed was the blue slime drop the yellow hearts ALOT, it seems it drops the hearts instead of slimeballs, so you get about 2 hearts per kill and almost no slime (think the droprates got switched up).
Edit: I disabled thaumcraft, ran the same world, the taint were gone, then I changed the config for thaumcraft to not allow taint spread, and decreased the chance of random taint biomes to as low as I could (1-100 I put it at 100 which is the lowest). Then i reenabled thaumcraft and so far no crashes.
It seems to me to be a bug that has to do with either the taint affecting enteties or taint spread. This solution worked for me anyway.