VBA UBound returns a negative value

VBA UBound returns a negative value

I would like to know what I'm doing wrong...
I have a word document open (in word 2010) with three tables in it. I wanted to test basic table extraction in VBA and followed the instructions http://msdn.microsoft.com/en-us/library/office/aa537149(v=office.11).aspx.
Sub ExtractTableData()
Dim doc As Word.Document
Dim tbl As Word.Table
Dim rng As Word.Range
Dim sData As String
Dim aData1() As String
Dim aData2() As String
Dim aDataAll() As String
Dim nrRecs As Long
Dim nrFields As Long
Dim lRecs As Long
Dim lFields As Long

Set doc = ActiveDocument
Set tbl = doc.Tables(1)
Set rng = tbl.ConvertToText(Separator:=vbTab, _
    NestedTables:=False)
' Pick up the delimited text into and put it into a string variable.
sData = rng.Text
' Restore the original table.
doc.Undo
' Strip off last paragraph mark.
sData = Mid(sData, 1, Len(sData) - 1)
' Break up each table row into an array element.
aData1() = Split(sData, vbCr)
nrRecs = UBound(aData1())
' The messagebox below is for debugging purposes and tells you
' how many rows are in the table.  It is commented out but can
' be used simply by uncommenting it.
'MsgBox "The table contained " & nrRecs + 1 & " rows"
'Process each row to break down the field information
'into another array.
For lRecs = LBound(aData1()) To nrRecs
    aData2() = Split(aData1(lRecs), vbTab)
    ' We need to do this only once!
    If lRecs = LBound(aData1()) Then
        nrFields = UBound(aData2())
        ReDim Preserve aDataAll(nrRecs, nrFields)
    End If
    ' Now bring the row and field information together
    ' in a single, two-dimensional array.
    For lFields = LBound(aData2()) To nrFields
        aDataAll(lRecs, lFields) = aData2(j)
    Next
Next
End Sub
I'm getting an error at this line: ReDim Preserve aDataAll(nrRecs, nrFields), which is due to "nrFields" being set to a negative value (-1)...
No idea how the upper bound of the array is a negative value... Any help on this would be much appreciated.