This can happen if the system is under heavy load, or if it's running out of some critical resource like memory or file descriptors.

Here are a few steps you can take to address this issue:

1. Check System Resources: First, make sure that your system has enough available resources, including memory, file descriptors, and CPU capacity. You can use commands  free -m to check memory usage and ulimit -n to check the maximum number of open file descriptors.

2. Reduce Load: If the system is under heavy load, try to reduce the load by stopping unnecessary processes or tasks.

3. Increase Resource Limits: You can increase resource limits for your shell or for specific processes. For example, you can use ulimit command to increase the number of file descriptors available to a process.

4. Optimize Your Code: If you're a developer, review your code to ensure that you're properly closing resources (like files) after using them. Leaving too many open can cause this issue.

5. Consider Hardware Upgrades: If you're consistently running into resource limitations, you might need to consider upgrading your hardware (e.g., adding more RAM).

6. Check for Fork Bombs: In some cases, this error could be caused by a fork bomb—a malicious or poorly written script that rapidly creates new processes, overwhelming the system. Ensure that your system isn't under attack from such a script.

7. Review Logs: Check system logs (like /var/log/messages or /var/log/syslog) for any relevant error messages or warnings that might shed light on the cause of this issue.

If none of these steps resolve the issue, you may want to seek help from your system administrator or consult a technical support forum related to your specific operating system and environment for more tailored advice.