error in Worksheet_Change with merged cells

My intention is that in certain cells are put certain values and if not for that cell as far as to call attention to put the red background color and font color to black and become the cell of the error ( I try to avoid the MsgBox).
Worksheet_Change line 2 put it with the intent that if given the delete key or space is the cell with white background and no data.
So there I was fine, but do try a combo, this X15 combined with Y15 (for a matter of design of the template), I get error 13 Type Mismatch?? I don't know to have!
I apologize because I am using a translator from spanish, sorry!