The error you got seems to align with the driver linked at the very top of this thread, which only works for the old OTZ firmware files, not the GBL files. That github repo has a binary version in it, but also the guide that I linked to specifically has a link to a forked version which fixes a bug and adds a couple features.
You need to use one of the "Binary" versions that can handle GBL files.
Original: hubitat/Drivers/Z-Wave-Firmware-Updater/zwaveBinaryUpdater.groovy at master · djdizzyd/hubitat · GitHub
Forked: [BETA] Updated binary firmware updater
hubitat/Drivers/Z-Wave-Firmware-Updater/zwaveBinaryUpdater.groovy at master · mbbush/hubitat · GitHub
Guide: [GUIDE] Z-Wave device - how to update firmware using the driver method
