Hi,
following steps may be help you to get the requirement:
1.go to report--> selection formulas-->record-->select n option as "default values for null " that exist beside comment (//) option.
2.Write following formula:
not (isnull({Customer.Address2}))
(formula will give you data that has no null values.)
3.Now insert you chart into the report,you will get chart without spaces.
Resolution2:
1.You must get your data to the report without null by using add command(free hand sql)
2.you insert the chart.you will get chat without spaces.
Thanks,
Sudh.