dscope problems

When using dscope I'm getting strange occurrences in the serial window

My code is:

#include <stdio.h>
main()

{
char c;
while ((c = _getkey()) !=0x1B){
printf ("key = %c\n",c);
}
}

When the program is run, in the serial window, "key =" keeps repeating itself down the screen, even though no key has been pressed. As I am very new to this device it could be something very simple so any ideas would be grateful.