Something to try. What if instead of checking each cell for it's border size, you just set the entire table to 1pt? Would that speed things up?

As far as the Option Explicit issue, it simply means you have to declare each variable before you can use it. For example,
Dim objTable As Table
Dim someVar As Integer
Dim someVar As String
Dim someVar As Variant
Dim someVar As Object
etc