The scancode for the print key is not forwarded to the dos application.
What exactly are you trying to do?

civmap21, is a program that modifies the current world map in civilization 1. The package provides instructions to modify the civ.exe executable such that after one loads civmap21.exe, then starts civ.exe normally, the user hits "Print Screen" and it invokes the civmap21 code in memory allowing one to change the map s/he is playing on. I got it to work years and years ago on an old machine, but dos on VMWare or many of the others fail to run civ.exe properly so even though "Print Screen" is active, it is of no use. If I knew what the modifications to the civ.exe file in hex were doing I could perhaps map the action to a different key, but I don't have the knowledge (yet, I am starting my junior year as a computer engineer and we will be doing a lot of hardware stuff this year). Attached is the instruction text file.

If I knew what the modifications to the civ.exe file in hex were doing

Well it just calls two interrupts (cd f1 and cd f2 are intf1 and intf2) which might
be grabbed by the map editor.
So you can't just change those hex edits to use a different key.

Thanks for your help, I'll keep looking. Impressive work with DOSBox by the way, the compatibility list is just astounding.