@wacrossland said in Error Message: "Printer not in delta mode":
The version of the firmware I am using is VERSION: 1.09k-dc42
That is very old firmware! I suggest you upgrade to either version 1.25RC4 available at https://github.com/dc42/RepRapFirmware/releases/tag/2.04RC4, or 1.23 from https://github.com/dc42/RepRapFirmware/releases/tag/2.02 (it says 2.02 but the build for Duet 085 is 1.23). Don't use version 1.24, it has a bug affecting delta printers.
After upgrading, re-test everything very carefully. It's quite likely that some changes to config,g will be needed, but going back that far I can't remember what. One of the changes that happened way back was that the default X axis direction changed (or X tower in the case of a delta).