failed to contact the name server (Orocos::CORBAError)

The CORBA layer needs a name service to find out what components are available, and how to contact them. This message appears when this name service cannot be contacted. There can be the following reasons:

• the Orocos::CORBA.name_service attribute, used to specify the hostname of the name service machine, is set to a wrong value.
• there is a firewall blocking TCP port 2809

• the name service is not running on the machine you think it is. You can check that with

  sudo netstat -tl

  If the service is running, there should be a line starting with ‘tcp’ and ending with 2809/omniNames.

On Debian and Ubuntu, the OmniORB nameserver startup script does not report an error if the name service startup failed. If you have checked (as above) that the name service is not running, you can start it by hand to see why it is not starting with

sudo omniNames

Sometimes, the service’s log file gets corrupted. In that case, the above command will yield an error looking like:

Error: parse error in log file '/var/lib/omniorb/omninames-mercury.log' at line 1.

The best solution then is to simply delete all omninames log files with

sudo rm -f /var/lib/omniorb/*