Dynamic chart problem
 

I am following the example from 'Peltier' site.
All goes well until I get to changing the chart's data source.
It tells me to insert the following formula:
=Series(Data!$AI$1,Data!$AH$2:$AH$10,Data!$AI$2:$A I$10,1)
But with no luck, I get the following message "THAT FUNCTION IS NOT VALID"
Any ideas