Pie chart in Summary section error with <no message> in Report State tab

[michael.anatole]

I have a pie chart in the summary that when run gives the following error message: Error Generating Report.

Contains : <no message> in Report State tab with an Error count of 1.

I have a simple SQL query : select count(*) as students, agegroup from attendance group by agegroup

Returns 

474;"Young Adult    "

426;"Teen           "

3010;"Youth          "

2479;"Adult          "

1613;"Senior         "

 

 

Value = $F{students}

Label = $F{agegroup}

Key = IF($F{agegroup}==null,"empty",$F{agegroup})

 

Report is fine when NOT running with chart. 

 

What could be the problem here. Confused!

 

Please advise!