Delete Word Button Using VBA

[cloudcover]

How do I delete a button in Word 2010, using VBA? I'm using this code:

Dim o As Object
For Each o In ActiveDocument.InlineShapes
If o.OLEFormat.Object.Caption = "Test" Then
o.Delete
End If
Next

It worked for a few days, but now I get an 'Object variable or With block variable not set' error.

Thanks