I run into this error only with one of several db's which all
have same Semaphore settings, though different Hardware
config. All SUN boxes are dedicated to run Oracle only.

--basic config of the troubled box:

SUN Sparc/Solairs 7/256 MB RAM
Oracle 805

set shmsys:shminfo_shmmax=4384354560
set shmsys:shminfo_shmmin=1
set shmsys:shminfo_shmmni=100
set shmsys:shminfo_shmseg=10

set shmsys:seminfo_semmni=1000
set shmsys:seminfo_semmns=1000
set shmsys:seminfo_semmsl=200

set shmsys:seminfo_semmnu=200
set shmsys:seminfo_semume=50

any help will be greatly appreciated !!