This is related to dispatcher (MTS/Shared server).
The dispatcher was unable to spawn a new shared server process to handle requests.
When you are running shared server (MTS) and more shared servers need to be started, they are automatically started up to the number of max shared servers specified in the init.ora file.
This problem is occurring because you are running out of resources on your machine that are required for the servers to startup.
1. Increase swap or memory.
2. Reduce the number of shared servers (dispatchers) that can be started.
It is better to ask and appear ignorant, than to remain silent and remain ignorant.