if I forget to enter a value in a cell in my gridview a loooong error who says thar that the indata format is wrong. anyone who know where in visual studio I can make this error a bit more understandable for others?

If you are using the Try/Catch statement as the following code,

Try
            '// your code here that might cause the error.
        Catch ex As Exception
            MsgBox(ex.Message) '// display the default message, which in your case is probably the message your get.
        End Try

you can easily modify the Message to yours, like so.

Try
            '// your code here that might cause the error.
        Catch ex As Exception
            MsgBox("Found an Error, etc., etc., etc.", MsgBoxStyle.Critical, "Error") '// display your message.
        End Try