All pipe instances are busy

Hi all,

I've got following error message from an NT System:

EventID: 0x80001B6F (7023) - The OracleServiceOTB service terminated with the following error:
All pipe instances are busy.

Could someone tell me what does "All pipe instances are busy" mean?

Thanks,
Yves

http://www.jsiinc.com/TIP0300/rh0348.htm
I don't know yet how to increase the limit.