Selecting resource packs does not work

Selecting a resource pack in the resource pack selection menu does not work. Smaller packs (<10MB) do not load, larger packs (>80MB) crash the game. A crash report is attached to the ticket.
Tested it with a converted version of the "Better than Default" texturepack and my 256x256 WIP texture project. Both folder based packs and zip-files do not work, editing the "skin" tag in options.txt still allows changing textures though.