datagridview problem with calender

hi,

i added a datetimepicker to one column of datagrid. i got this by downloading generic datgrid user control from web. after i download that control, i got the 'calendercolumn' also as columntype. it is working. but when i ma trying to insert one row thru datagridview to sql table' s datetime column, when i am clicking on the calender cell value itself it is giving me the following error.



"to replace this default dialogue please handle the data error event...............

System.InvalidCastException was unhandled by user code
Message="Specified cast is not valid."
Source="GenericDataGridView"
StackTrace:
at GenericDataGridView.GenericDataGridView.CalendarCell.InitializeEditingControl(Int32 rowIndex, Object initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle) in C:\Documents and Settings\c0001014\Desktop\vs2005Projeler\GenericDataGridView\GenericDataGridView\GenericDataGridView .cs:line 504
at System.Windows.Forms.DataGridView.InitializeEditingControlValue(DataGridViewCellStyle& dataGridViewCellStyle, DataGridViewCell dataGridViewCell)