We were using the mechanism of 'StartupItems' to create the service for the GECAMed server on Mac OSX. This mechanism has been marked as deprecated a few Mac OSX versions ago, and starting with Mac OSX 10.10 (Yosemite) it is no longer supported at all.
Now the recommended way to create a service on Mac OSX is to create a 'launchd' daemon.
Starting with GECAMed version 2.01.01 the installer and updater are using the new mechanism. If you have an older version and cannot update for some reason, you can also change it manually.
You'll need a user with administrator privileges to do the following operations.