I've added a context menu to the "Folder" file type, which opens a DOS box at the current folder. The command line I use for this is:
command.com /k dosbox

This method works fine, running a little batch file called "dosbox" from the windows folder, then leaving me at the command prompt, with the current directory set to the folder from which I launched.

When "playing" with this though, I tried using a modified dosprmpt.pif to achieve the same result. I simply added the parameter C:WINDOWSDOSBOX as the Batch file in the Program tab of the Properties. I then used the command line:
C:WINDOWSDOSPRMPT.PIF for the new "DOS Box" folder option.

This works too, except that I get this message as the first line in the DOS box:
Specified COMMAND search directory bad

I've hunted around, as to its possible source, but can't find anything of value. Can anyone enlighten me?