EMC Following Error

I am trying to get EMC working with a small mill. I have Gecko G320 drivers
and am using steppermod. I can jog the axes back and forwards by the amounts
I expect and in the right directions. However, I occasionally get following
errors and do not understand why.

The emc.ini parameters that I think are relevant are:
TASK = minimilltask

; Trajectory Planner
section --------------------------------------------------
EMCMOT = steppermod.o
DEFAULT_VELOCITY = 0.0167
MAX_VELOCITY = 1.2
DEFAULT_ACCELERATION = 20.0
MAX_ACCELERATION = 20.0

; Axes
sections ---------------------------------------------------------------
; First axis
[AXIS_0]

TYPE = LINEAR
UNITS = 0.03937007874016
HOME = 0.000
MAX_VELOCITY = 1.2

INPUT_SCALE = -32000 0
OUTPUT_SCALE = 1.000 0.000

FERROR = 1.000
MIN_FERROR = 0.010

I have other questions about the emc.ini file but I'm happier taking one
step at a time!

Regards,

Dave.

David Micklethwaite