Hi Ganimede,
Could you try setting following parameters in the file /etc/system:
For mpi/max_pipes of 4,000:
set semsys:seminfo_semmni=500
set semsys:seminfo_semmns=50000
For mpi/max_pipes of 20,500:
set semsys:seminfo_semmni=1000
set semsys:seminfo_semmns=50000
Values for mpi/max_pipes should be calculated based on SAP note 737625.
Additionally try to change the descriptors settings for root user ( currently its 256) to 2048 and check the results.
Hope this helps.
Regards,
Deepak Kori