What causes a 'program contains a Concept loadable' error in Modsoft?

This message is a result of IEC being enabled in the PLC when the project was uploaded/downloaded using Modsoft.

There is nothing that can be done that will allow Modsoft to read the project from the PLC if it is IEC. Concept must be used.

If seeing the error when writing the project using Modsoft:

If powering down for at least 1/2 hour and then powering up with the memory protect switch on does not correct it then this means that the Quantum has been flashed with stripped IEC firmware. You will need to load the standard quantum firmware to it for use with Modsoft.

Take a look at the InfoSR document that is included in the Concept install folder to determine which firmware is needed.
The firmware files can be located in your Concept\DAT directory.