It looks like you need Jackpot help instead of MillMage help. If there is ANY valid GCode in that file, you should be able to run it.
Why are you not using MillMage to control the machine? I did a Google and found this…
Yes, MillMage officially supports FluidNC
for full machine control and G-code generation. [1, 2]
Connection and Setup Details
- Device Selection: You can set up FluidNC controllers directly, or select the standard GRBL dialect/profile type within MillMage since FluidNC uses the GRBL command structure. [1, 2]
- Network Connections: When connecting over a network, users on the LightBurn Software Forum note that FluidNC supports TCP/Telnet connections (typically using port 23) for direct software control. [1]
- Compatibility Range: It is listed natively across official MillMage Documentation alongside GRBL, grblHAL, and Smoothieware. [1, 2]