This computer game is based on BrainTeaser by Wim Nijland.
Choose digits from 1 to 9, split by reaction method into three groups: 1-3-7-9, 2-4-6-8, and 5.
The goal is to display all digits except 5, avoiding the field clearing.

The source code in Xtal Basic is attached —

Using EDIP, write the source code to a floppy disk and load it through the MAME emulator.
It works in Xtal Basic 4.2 and 5.0.

However, cannot save it with the SAVE command in any form due to a “Bad Data” error, and have the same problem with compilation.
What could be the reason?

A boot disk containing the compiler and source code is attached.

Compiled it using a CP/M-compatible operating system on MSX. The result, which requires the runtime (xr.com from the compiler package), is attached below.