This message is issued only if inetd is started with the debug (-d) option and the return value to select() is -1. The most common return_code is EINTR, indicating that a signal has been received. Generally, this is from a SIGCHLD when a child process terminates. When that occurs, message FOMN0020 will have been issued.
If an EINTR has been received, inetd re-issues the select(). For other errnos, message FOMN0008 and possibly FOMN0009 are issued.
If FOMN0008 or FOMN0009 is issued, see the response for those messages.