Deleting rows in gridview after clicking a button

Hi,
  I am working on deleting the selected rows from the gridview after clicking a delete button, i have provided one column with checkboxes in gridview after checking of check boxes click on delete button here iam getting error like incorrect syntax near ',' how to solve this error, please can anyone help me. i have sent my sample code through attached file in that deleting rows code is there in default.aspx page please refer it what is the mistake inform me.



With Regards
Kavya