Change Applescript Actions Based On Key?

I'm writing an Applescript, and distributing it to many different people. What I want it to do is go through the actions normally, but if the "C" key is held down, it goes to the config window. I'm running Mac Os 10.7.5, normal Applescript. What I have so far is:

tell application "System Events"
  
                    try
  
                              if keystroke "C" is down then
  
                                        beep 5
  
                              end if
  
                    on error
  
                    end try
  
          end tell

It compiles and runs, but doesn't react when I press the "C" key, even when I set it to endlessly repeat. Is there a working version of this?