Some Mac applications crash frequently, with "__THE_SYSTEM_HAS_NO_PORT_SETS_AVAILABLE__" in backtrace

I'm not a kernel programmer, but I'm guessing that message has something to do with running out of Mach ports in the kernel. Do you have a zillion processes running, or are you doing a lot of inter-process communication? Are you possibly low on memory and disk space (no room to expand your swap)?

Try using top or Activity Monitor to see if you have any processes going crazy, like perhaps you've written a recursive AppleScript or shell script that's spawning zillions of child processes (like an accidental "fork bomb").

Pay attention to what apps you have running when you hit this crash. Maybe there's an app that overuses Mach ports and sometimes gobbles them all up. Is this problem more likely to hit when you're running a virtual machine system such as VMware, Parallels, or VirtualBox?