Adding A New Sheet Which Includes A "change" Event

As per the following code I'm trying to add a new sheet which should inclide the CHANGE Event Proc

Unfortunatelly, I get an error message (free translation from Hebrew):
====================
RunTime Error '1004':
"Programming entrance to the Visual Basic Project is not secured".
===========================================
Here is the code I used:

Sub AddSheetWithCode()
Dim StartLine As Long
Sheets.Add
With ActiveWorkbook.VBProject.VBComponents(ActiveSheet. Name).CodeModule
StartLine = .CreateEventProc("change", "worksheet") + 1
.InsertLines StartLine, _
"if not intersect(target,range(""a1:a10"")) is nothin then" & Chr(13) & _
"if target=10 then" & Chr(13) & _
"target.clearcontents" & Chr(13) & _
"msgbox (""Bla...."")" & Chr(13) & _
"end if" & Chr(13) & _
"end if" & Chr(13)
End With
Application.VBE.MainWindow.Visible = False
End Sub

how to eliminate the error.