Runtime error on Sort

I am getting a runtime error performing a Sort. The extended File Sttus is 011. Which according to the documentation (if I am reading it right) states that it is the following. How can I get this to work?

COBRT011 Process limit reached (Fatal)

One of the following has occurred:
  • The run-time system cannot create a new process as the operating system limit on the total number of processes per user or system-wide would be exceeded.
  • Insufficient memory is available to complete the operation.

Resolution:

Terminate any processes that you are no longer using, or make more memory available.

Your operating system might enable you to increase the maximum number of processes allowed. Refer to your operating system documentation for further information.