To debug using an xterm, first set debug_method to ADM_XTERM. If the DISPLAY environment variable is not set (or set incorrectly), set debug_method_string to point to your X server.
At execution time, the ACUCOBOL-GT runtime creates an xterm with the COBOL program stopped at the first line of the program.
Note that when the debugger starts, debugger settings are loaded from a file, and changes to settings are saved to that file as the debugger runs. By default, that file is given the name of the user who started the background or server process. In some environments, this could mean that multiple users of the debugger could share the same debugger settings. In such a case, breakpoints set or cleared by one user, for example, would affect what appeared in every other user's debugger window.
To avoid this potential problem, use the "acudebug.user" X resource to specify separate debugger settings files for different users. For example, in your "/.Xdefaults" file, you could add the line:
acudebug.user: dsmith
Debugger settings would then be loaded from and saved to a file called "dsmith.adb".
See your X server resource database documentation ("man xrdb") for additional instructions on how to set X server resource properties.