Your logfile is unreadable since all lines are concatenated to a single line.
Generally, if suddenly null-refs appear, I would advise to stop the game, make a backup of the savegame and then start up again. If no further null-refs appear the damage was probably confined to memory and not saved to disk. If it reappears, then a check of the logfile is necessary to find out which part of the savegame was damaged and whether it can be repaired.