VBA why am i getting error or popup saying "16" - excel

Question

In the code shown below, i am in the first section moving data from sheet "Ark2" to the sheet "Ark1". in the second section, i transpose from vertical to horizontal. Now i am rinning it in module, but i am getting an popup saying "16" and it is deleting data from my sheet "Ark2" and therefor also data on ark2.
it is not adding data from the first sheet to the second or horizonting the colums.
hope you can help!!
Sub MyProcedure()
a = Worksheets("ark1").Cells(Rows.Count, 1).End(xlUp).Row
MsgBox (a)
End Sub
Private Sub CommandButton1_Click()
Dim nøgletal As String, år As Integer
Worksheets("Ark2").Select
nøgletal = Range("B2")
år = Range("C2")
Worksheets("Ark1").Select
Worksheets("Ark1").Range("A4").Select
ThisWorkbook.Worksheets("Ark1").Range("C1:C100").Value = ThisWorkbook.Worksheets("Ark2").Range("C12:C100").Value
ThisWorkbook.Worksheets("Ark1").Range("D1:D100").Value = ThisWorkbook.Worksheets("Ark2").Range("D12:D100").Value
ThisWorkbook.Worksheets("Ark1").Range("E1:E100").Value = ThisWorkbook.Worksheets("Ark2").Range("M12:M100").Value
ThisWorkbook.Worksheets("Ark1").Range("F1:F100").Value = ThisWorkbook.Worksheets("Ark2").Range("N12:N100").Value
ThisWorkbook.Worksheets("Ark1").Range("G1:G100").Value = ThisWorkbook.Worksheets("Ark2").Range("O12:O100").Value
ThisWorkbook.Worksheets("Ark1").Range("A1:A16").Value = ThisWorkbook.Worksheets("Ark2").Range("A12:A16").Value
If Worksheets("Ark1").Range("A4").Offset(1, 0) <> "" Then
Worksheets("Ark1").Range("A4").End(xlDown).Select
End If
ActiveCell.Offset(1, 0).Select
ActiveCell.Value = nøgletal
ActiveCell.Offset(0, 1).Select
ActiveCell.Value = år
Worksheets("Ark2").Select
Worksheets("Ark2").Range("B2", "B16").Select
End Sub
Sub x()
Dim lngDataColumns As Long
Dim lngDataRows As Long
lngDataColumns = 3
lngDataRows = 4
For t = 1 To lngDataRows
Range("l2").Offset(((t - 1) * lngDataColumns) - 1, 0).Resize(lngDataColumns, 1).Value = _
Application.Transpose(Range("e1:g1").Value)
Range("M2").Offset(((t - 1) * lngDataColumns) - 1, 0).Resize(lngDataColumns, 1).Value = _
Application.Transpose(Range("e1:g1").Offset(t).Value)
Next t
End Sub

Answer 1

why am i getting error or popup saying “16”
Should be evident why if you add a value in say ark1!A17 and rerun:
Sub MyProcedure()
a = Worksheets("ark1").Cells(Rows.Count, 1).End(xlUp).Row
MsgBox (a)
End Sub
If not, try adding also into ark1!A18 and rerunning.