This problem looks very unique. I think you might need the help from oracle. before that please give me following informations.
1. Your operatin syste, with versions
2. oracle database version.
3. The value of PROCESS from the init parameter file
4. the value of SEMMSL and SEMMNS from the /etc/system file if the OS is unix
5. permissions of $ORACLE_HOME/bin if the OS is Unix
Please post with this values,
Thomas P S