Laser stops and Lightburn gives integer error

"a line in the GRBL code needing to be an integer"

There’s nothing wrong with the G-Code, so this is almost certainly a USB glitch that’s very hard to track down.
Changing to a known-good / high-quality USB cable sometimes helps; ones with ferrite slugs on each end may have a higher likelihood of improving the situation.
If there’s a USB hub involved, eliminate it and run the cable directly from PC to laser controller.
If there’s a USB extension cable involved, it must be an active cable, not a simple extension. If at all possible, use a single good cable.

USB 3 ports seem to work better, except when they don’t work at all.
Fiddling with settings / drivers / configurations / whatever will not change the situation and will cause more problems by confusing the symptoms.