This error occurs when installing or running an upgrade of Fortis. This is caused by one or two things.
1) If you are running a new install, make sure you are pointing to the unzipped location of the configuration files you were sent.
2) If you are running an upgrade, make sure you point to the Upgrade folder within the cdmedia folder (the install media).
3) If you still receive the error message after you point to the Upgrade folder; please download the following file, unzip it, and place it in the Upgrade folder.
2.5.0 - http://cdn.westbrooktech.com/idx/250idx02_1.zip
2.6.0 - http://cdn.westbrooktech.com/idx/260idx02_1.zip
2.7.0 - http://cdn.westbrooktech.com/idx/270idx02_1.zip
2.8.0 - http://cdn.westbrooktech.com/idx/280idx02_1.zip
6.8.0 - http://cdn.westbrooktech.com/idx/680idx02_1.zip
6.9.0 - http://cdn.westbrooktech.com/idx/690idx02_1.zip
6.10 - http://cdn.westbrooktech.com/idx/610idx02_1.zip
6.11 - http://cdn.westbrooktech.com/idx/611idx04_1.zip