M136 not allowed with FU/FZ
Cause of error
In an inch program you combined the FU functions (feed rate in in./rev) or FZ (feed rate in in./tooth) with the M136 function (feed rate in 0.1 in./rev).
Do not use both functions simultaneously in an NC program. HEIDENHAIN recommends using the FU or FZ function because it enables you to enter the feed rate here directly in in./rev or in./tooth.