SCO OpenServer Handbook
Chapter 3, Troubleshooting the installation
Error message: Can´t fork

Error message: Can´t fork

If your system swap space is insufficient, you may see error messages such as: 

   Can't fork
In general, the default amount of swap space assigned at installation time is sufficient, but if your machine is heavily loaded with graphical or other processes, you should increase the amount of swap space using swap -a. See the swap(ADM) manual page.