I am getting this error:

heller@debian:~$ ./Digital_Character_Sheet_3-v1-Demo.AppImage

(Digital_Character_Sheet_3-v1-Demo.AppImage:5462): Gdk-ERROR **: 15:42:46.865: The program 'Digital_Character_Sheet_3-v1-Demo.AppImage' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadAccess (attempt to access private resource denied)'.
(Details: serial 180 error_code 10 request_code 130 (MIT-SHM) minor_code 1)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the GDK_SYNCHRONIZE environment
variable to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)
Trace/breakpoint trap

(This is in a minimal x86_64 Debian 12 VM hosted on a Raspberry Pi5 running ARM64 Debian 12)