To look if the problem is with the total number of processes
you can install and configure the PDT (Perfomance Diagnostic
Tool). To configure run:

/usr/sbin/perf/diag_tool/pdt_config

Collect data for a week and run the report

/usr/sbin/perf/diag_tool/pdt_report

If the problem is with nprocess change it.

To see the actual value

lsattr -E -l sys0

to change:

chdev -l sys0 -a maxuproc=600

Regards. Hugo.