Command not found usually indicates a typo or a package that isn't installed. In this case, my offhand guess would be a typo. By using the TAB auto-complete built into Bash you can save yourself from this problem. It may be that /etc/init.d/sysklogd is NOT the correct call. If you:
You can see what is there to restart. It may be sysklog or syslogd or something else entirely. I assume you are following instructions from some source, it may assume you have a specific package installed that you don't. Check the documentation a bit.