This is not the same problem, since in this case the reason the worker process failed is because of a "Cannot allocate memory" error when trying to spawn a subprocess.
Here is a good link which explains the usual reasons for this (and a possible solution):
https://stackoverflow.com/questions/...llocate-memory
tl;dr
You ran out of RAM, either for real or because the subprocess wanted to reserve the right to access more RAM than you had available.