Mac 2.4GHz Core 2 Duo, 6GB RAM, OS X 10.9.5
Opened Admin Console and turned off all server services (even auto start). Same error message.
Restarted machine, still got the error.
Checked all file and folder permissions. Everything "Read-Write".
I decided to update after getting "database not modifiable" errors on some served files (not all).
p.s. I guess reinstalling FMS 13 is an option. I might also just switch to FMS 14. I have some clients using FMS 13, so I decided to stick with FMS 13, but I probably should update.