Charting Error

Hey Guys,
I am now getting an error message "An XML Element was malformed" when trying to view one o my charts.
Here is my SQL script if that helps:
SELECT

cdate,

COUNT(callticket) AS ['Total Orders per Month'],

DATEPART(mm, cdate) AS ['Month'],

CASE DATEPART(mm, cdate)

WHEN '12' THEN 'Dec'

WHEN '11' THEN 'Nov'

WHEN '10' THEN 'Oct'

WHEN '9' THEN 'Sept'

WHEN '8' THEN 'Aug'

WHEN '7' THEN 'Jul'

WHEN '6' THEN 'Jun'

WHEN '5' THEN 'May'

WHEN '4' THEN 'Apr'

WHEN '3' THEN 'Mar'

WHEN '2' THEN 'Feb'

WHEN '1' THEN 'Jan'

END AS ['MONTH'1]

FROM client_support

GROUP BY cdate, DATEPART(mm, cdate)

ORDER BY DATEPART(mm, cdate) DESC