"no more processes"

[Martin Dorschler]

Just had a box go unresponsive on all services (still pingable) had a session 
still open to it but any command would result in the error "no more processes" 
Checks clean for a rootkit and nothing amiss in the logs (that I can find).
I have never heard of a bsd box giving this error before, I can't even think of 
what (other than a hack) would cause such an ungraceful freeze.

Any suggestions welcome.

M