Problem: a parallel task cannot be launched, an error is reported:

  PSI: PSI_createPartition: Resource temporarily unavailable

Check for available nodes and active parallel tasks. Check for user or group restrictions.

If the error

  PSI: dospawn: spawn to node 1 failed.
  PSE: Could not spawn './mpi_latency' process 1, error = Bad \
    file descriptor.

is reported, check if the current directory holding the program mpi_latency is accessible on all nodes. Verify that the program is executable on all nodes.