VBA Proper error 13

I have created a code to auto capitalise a column and auto proper another column.
The code works until I try to delete data from the proper column and I then get an error code which I cannot figure out how to correct.
Any help would be much appreciated.

Private Sub Worksheet_Change(ByVal Target As Range)
Application.EnableEvents = False
If Not Intersect(Target, Range("I:I")) Is Nothing Then
Target.Value = UCase(Application.Substitute(Target.Value, " ", ""))
End If
Application.EnableEvents = True
Application.EnableEvents = False
If Not Intersect(Target, Range("D:D")) Is Nothing Then
Target.Value = StrConv(Target.Value, vbProperCase)
End If
Application.EnableEvents = True
End Sub

Thank you for your reply Tom.
It only seems to happen if I select multiple cells and press delete.

You could also use On Error Resume Next

Private Sub Worksheet_Change(ByVal Target As Range)
On Error Resume Next
Application.EnableEvents = False
If Not Intersect(Target, Range("I:I")) Is Nothing Then
Target.Value = UCase(Application.Substitute(Target.Value, " ", ""))
End If
Application.EnableEvents = True
Application.EnableEvents = False
If Not Intersect(Target, Range("D:D")) Is Nothing Then
Target.Value = StrConv(Target.Value, vbProperCase)
End If
On Error GoTo 0
Application.EnableEvents = True
End Sub

It is always better to write a code to handle multiple cells change and use of vba native function...

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim r As Range
    Application.EnableEvents = False
    If Not Intersect(Target, Columns("I")) Is Nothing Then
        For Each r In Intersect(Target, Columns("I"))
            r.Value = UCase(Replace(r.Value, " ", ""))
        Next
    ElseIf Not Intersect(Target, Columns("d")) Is Nothing Then
        For Each r In Intersect(Target, Columns("d"))
            r.Value = StrConv(r.Value, 3)
        Next
    End If
    Application.EnableEvents = True
End Sub

Thanks to you both, working fine now.
Have add rep both.
Cheers.