The error says " Run-time error '9': Subscript out of range". The excel workbook doesn't have any details in it when created. I debugged the code to see where it is failing. Its failing here 

For i = 1 To .Comments.Count 
            With .Comments(i) 
                StrCmt = StrCmt & vbCr & .Reference.Information(wdActiveEndAdjustedPageNumber) & vbTab & .Range.ListFormat.ListString & vbTab & .Author & vbTab & .Date & vbTab & .Scope 
                StrCmt = StrCmt & vbTab & Trim(Split(.Range.Text, ":")(0)) & vbTab & Trim(Split(.Range.Text, ":")(1)) 
            End With 
        Next