My object browser says

VisibleBounds As Variant
Member of InDesign.PageItem
The bounds of the page item including the stroke.

So, why does the following code give me a "type Mismatch: 'PageBounds'"?

Set myIndesign = CreateObject("Indesign.Application.2.0")
Set Doc12up = myInDesign.ActiveDocument

'Loop through each selected item
For x = 1 To Doc12up.Selection.Count
'set oPageItem object to item in pageitems collection
Set oPageItem = Doc12up.Selection.Item(x)

If TypeName(oPageItem.Parent) = "Page" Or TypeName(oPageItem.Parent) = "Spread" Then
Set CurrentPage = oPageItem.Parent
If TypeName(CurrentPage) = "Spread" Then
Set CurrentPage = CurrentPage.Pages.Item(1)
End If


PageBounds() = oPageItem.VisibleBounds
PageWidth = PageBounds(3) - PageBounds(1)
PageHeight = PageBounds(2) - PageBounds(0)

End If
Next