Chart (invalid data)

I have a field in table master named TM with a field idmilieu witch is related to table tmilieu (idmilieu, description) without lookup every thing is alright but when i make a lookup to tmilieu to bring description the summary is ok but the chart not draw (invalid data message)
Please can somebody help me ?

Is there a numeric value w.o. a numeric, i.e. a null or alpha chars in a numeric value?

Merci pour votre r?ponse

I note that if I do not use the lookup in the field the graph is displayed normally, but I even set the field idmilieu to a value that exists in the detail table and it still does not work. I will point out that if I removed the lookup from the field the graph works

The problem isn’t numeric or not because in my case i just do chart with record number case very simple, for information the field dont accept null or value not related in detail table. the application was working well before updating scriptcase to 7.014.