strange behavior when using datetime.Now.ToString(yyyy-MM-dd hh:mm:ss tt) to populate database column

I've been able to use
Dim UpdDate As TextBox = TryCast(FormView1.FindControl("UpdDateTextBox"), TextBox) UpdDate.Text = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss tt") to store the current time when a row is updated by putting this code in the FormView1_DataBound event in the past but when I try to use in my current webpage it errors out on the second line with
Object reference not set to an instance of an object. It errors out because of the second line above.  The strange behavior refers to the fact that I can click the update button to update the record with the updDate saved to the database table along with any other values (columns) I changed EXCEPT when I check the PendingBit checkbox. 
Here is some background info that you can skip but I put it in here in case it matter ...