Rendering screen java.lang.NullPointerException: Rendering screen (Superflat)

I was generating a new superflat world with a preset that I had came up with. The preset was something like this: 2;4x46,6x0,1x11,1x141,1x13,1x144:4,3x0,1x155,1x121,1x144:3,3x0,1x121,1x144:2,3x0,1x121,1x144,3x0,1x121,1x144:1,3x0,1x121,1x130,3x0,1x121,1x92,3x0,4x11,10x119,1x56,10x47,2x14,3x88,1x115,5x0,3x89,2x153,8x87,2x88,10x11,5x0,4x49,4x0,6x3:1,1x110,1x39,7x0,1x74,6x9,1x46,4x0,1x11,6x0,20x24,8x12,8x0,1x98:3,1x21,3x82,10x9,8x0,1x30,1x15,3x13,3x16,1x98:2,3x0,1x98:1,1x129,2x48,4x0,1x95:13,8x12:1,1x32,4x0,7x3:1,1x3:2,8x3,1x2;35;village(size=32 distance=8),mineshaft(chance=0.01),stronghold(chance=8 count=8 spread=8),biome_1(distance=8),dungeon,decoration

I was planning on making it into a sort-of adventure map, so that is why some things seem odd. ("Can you make it to the bottom?", etc. ) I was hoping to make multiple floors/layers, and I had thought that air layers would do the trick, but there is some crashing and the world will not even generate. When I view the layer screen itself with the icons of blocks, one of them or more seem to be crashing the game. If this is considered a "bug", I don't know which blocks exactly caused it, and my Minecraft menu has been lagging lately even though I turned the great battle of songs off. Seriously, one time I had eight songs all at once, and they all began at the same time and almost killed my ears due to max volume. Anyways, I hope that this can get fixed somehow, as the world that I am planning is awesome. 😃
Just ignore it if I posted too many error logs, it keeps happening anytime that I try to join the one world that I actually managed to create, and I think that those are the 2 server logs.