This error will occur if any of the Microsoft FRx and/or System files used by FRx Designer are not registered on the workstation.
To resolve this issue, do the following:
Browse to the Microsoft FRx root directory.
Locate and run the file FRxReg67.cmd. This will register the files necessary for FRx to function.
Note: When FRxReg67.cmd is run, a command window will open and then close.
Test FRx Designer again to see if the issue is resolved. If the error reoccurs, contact Microsoft FRx support to request the latest version of a .bat file that can be used to register all the shared system files. Once you receive that file, copy it into the Microsoft FRx root directory and execute it.