I think this is some forgotten bug in DFR. The error occures when you run DFR in portable-mode and open some app's folder as a DOS Box-Window (right click: files&folders - openDOSBoxprompt). Unless you have defined a special version of DOXBox for your game (like v0.72 for MSFS 1 + 2), you can ignore the message, because DFR uses the standard DOSBox from the program-folder (=the DOSBox.prof in the DOSBox directory or your DFR-folder). For non-standard-settings you can modify DOSBox.prof by hand (make a copy before). But in most cases: Click OK and it works anyway.

Tricia McMillan wrote:

I think this is some forgotten bug in DFR. The error occures when you run DFR in portable-mode and open some app's folder as a DOS Box-Window (right click: files&folders - openDOSBoxprompt). Unless you have defined a special version of DOXBox for your game (like v0.72 for MSFS 1 + 2), you can ignore the message, because DFR uses the standard DOSBox from the program-folder (=the DOSBox.prof in the DOSBox directory or your DFR-folder). For non-standard-settings you can modify DOSBox.prof by hand (make a copy before). But in most cases: Click OK and it works anyway.

Thanks