You might be running out of OS semaphores.

Try reducing the value for the parameter "processes" and try to
restart the instance. If it starts up fine and you still wish to increase
the number of processes, you will have to modify the /etc/system
file and increase the parameter and reboot the machine.

Another thing to check is the value for java_pool_size, set it to atleast
1M if you are on 8i ( if it is current value is less than 1M).

Good Luck!