The error is usually seen when you try to install a component of ours when you do not have a production database in place.

The installer looks in the Windows registry after specific keys to see if RE has been installed and where the plug-ins folder is located. The installer looks for the REINI_1 entry. If this does not exist then it assumes you do not have RE installed. However one problem with this is that some organisations testing will only install a sample database which by default has an entry of REINI_50 so of course, even though they do have RE installed the installer cannot find a production database so assumes that it does not exist.