an error message using RRDTool

Hi Guys;

Using RRDTOOL on a Windows based system, for the 1^st Time, working on the Tutorial, and discovered an error message and would like someone to help resolve asap Shown below:

C:\wamp\www\rrdtool\rrdtool-1.2.27-w32>rrdtool graph speed4.jpg --start 920804400 --end 920808000 --vertical-label km/h DEF:myspeed=test.rrd:speed:AVERAGE "CDEF:kmh=myspeed,3600,*" CDEF:fast=kmh,100,GT,100,0,IF CDEF:over=kmh,100,GT,kmh,100,-,0,IF CDEF:over=kmh,100,GT,kmh,100,-,0,IF CDEF:good=kmh,100,GT,0,kmh,IF HRULE:100#0000FF:"Maximum allowed" AREA:good#00FF00:"Good speed" AREA:fast#550000:"Too fast" STACK:over#FF0000:"Over speed"

ERROR: Attempting to reuse 'over'

it seems it does not understand 'over' in the IF ELSE statements: over=kmh ,100,GT,kmh,100,-,0, CDEF:over=kmh…

Best Regards,

David