The OSX kernel has a process table of a fixed size, and each process occupies one slot in the process table. The error "fork: Resource temporarily unavailable" is returned when OSX runs out of slots for new processes. The fix for this problem is to increase the number of slots included in the process table. This is done by adding a line like:

limit maxproc 512 2048

to the /etc/launchd.conf file (create it if it doesn't already exist). This sets the soft limit to 512 (the default is 100) and it sets the hard limit to 2048 (the default is 532). After you make this change, you must reboot for it to take effect. Until you reboot, the only thing you can do is quit some of your applications to free up process slots in the table.

-- DarrellSchiebel - 11 Jul 2006