What is your Aperture version, Eytan?
Is that the message you are getting?
That message usually will be shown, when Aperture cannot connect to the Internet to download the help text.
If you are connected to the internet, but still the help does not show, check, if a firewall or anti virus software (Little Snitch) may prevent Aperture from connecting to the server. Reboot.
Try the general trouble shooting steps: Aperture 3: Troubleshooting Basics
I'd start with removing the preferences and reinstalling Aperture.