Excel VBA - How to Redim a 2D array?

Question

In Excel via Visual Basic, I am iterating through a CSV file of invoices that is loaded into Excel. The invoices are in a determinable pattern by client.

I am reading them into a dynamic 2D array, then writing them to another worksheet with older invoices. I understand that I have to reverse rows and columns since only the last dimension of an array may be Redimmed, then transpose when I write it to the master worksheet.

Somewhere, I have the syntax wrong. It keeps telling me that I have already Dimensionalized the array. Somehow did I create it as a static array? What do I need to fix in order to let it operate dynamically?

WORKING CODE PER ANSWER GIVEN

Sub InvoicesUpdate()
'
'Application Settings
Application.ScreenUpdating = False
Application.DisplayAlerts = False
Application.Calculation = xlCalculationManual

'Instantiate control variables
Dim allRows As Long, currentOffset As Long, invoiceActive As Boolean, mAllRows As Long
Dim iAllRows As Long, unusedRow As Long, row As Long, mWSExists As Boolean, newmAllRows As Long

'Instantiate invoice variables
Dim accountNum As String, custName As String, vinNum As String, caseNum As String, statusField As String
Dim invDate As String, makeField As String, feeDesc As String, amountField As String, invNum As String

'Instantiate Workbook variables
Dim mWB As Workbook 'master
Dim iWB As Workbook 'import

'Instantiate Worksheet variables
Dim mWS As Worksheet
Dim iWS As Worksheet

'Instantiate Range variables
Dim iData As Range

'Initialize variables
invoiceActive = False
row = 0

'Open import workbook
Workbooks.Open ("path:excel_invoices.csv")
Set iWB = ActiveWorkbook
Set iWS = iWB.Sheets("excel_invoices.csv")
iWS.Activate
Range("A1").Select
iAllRows = iWS.UsedRange.Rows.Count 'Count rows of import data

'Instantiate array, include extra column for client name
Dim invoices()
ReDim invoices(10, 0) 

'Loop through rows.
Do

    'Check for the start of a client and store client name
    If ActiveCell.Value = "Account Number" Then

        clientName = ActiveCell.Offset(-1, 6).Value

    End If

    If ActiveCell.Offset(0, 3).Value <> Empty And ActiveCell.Value <> "Account Number" And ActiveCell.Offset(2, 0) = Empty Then

        invoiceActive = True

        'Populate account information.
        accountNum = ActiveCell.Offset(0, 0).Value
        vinNum = ActiveCell.Offset(0, 1).Value
        'leave out customer name for FDCPA reasons
        caseNum = ActiveCell.Offset(0, 3).Value
        statusField = ActiveCell.Offset(0, 4).Value
        invDate = ActiveCell.Offset(0, 5).Value
        makeField = ActiveCell.Offset(0, 6).Value

    End If

    If invoiceActive = True And ActiveCell.Value = Empty And ActiveCell.Offset(0, 6).Value = Empty And ActiveCell.Offset(0, 9).Value = Empty Then

        'Make sure something other than $0 was invoiced
        If ActiveCell.Offset(0, 8).Value <> 0 Then

            'Populate individual item values.
            feeDesc = ActiveCell.Offset(0, 7).Value
            amountField = ActiveCell.Offset(0, 8).Value
            invNum = ActiveCell.Offset(0, 10).Value

            'Transfer data to array
            invoices(0, row) = "=TODAY()"
            invoices(1, row) = accountNum
            invoices(2, row) = clientName
            invoices(3, row) = vinNum
            invoices(4, row) = caseNum
            invoices(5, row) = statusField
            invoices(6, row) = invDate
            invoices(7, row) = makeField
            invoices(8, row) = feeDesc
            invoices(9, row) = amountField
            invoices(10, row) = invNum

            'Increment row counter for array
            row = row + 1

            'Resize array for next entry
            ReDim Preserve invoices(10,row)

         End If

    End If

    'Find the end of an invoice
    If invoiceActive = True And ActiveCell.Offset(0, 9) <> Empty Then

        'Set the flag to outside of an invoice
        invoiceActive = False

    End If

    'Increment active cell to next cell down
    ActiveCell.Offset(1, 0).Activate

'Define end of the loop at the last used row
Loop Until ActiveCell.row = iAllRows

'Close import data file
iWB.Close

Answer 1

This isn't exactly intuitive, but you cannot Redim(VB6 Ref) an array if you dimmed it with dimensions. Exact quote from linked page is:

The ReDim statement is used to size or resize a dynamic array that has already been formally declared using a Private, Public, or Dim statement with empty parentheses (without dimension subscripts).

In other words, instead of dim invoices(10,0)

You should use

Dim invoices()
Redim invoices(10,0)

Then when you ReDim, you'll need to use Redim Preserve (10,row)

Warning: When Redimensioning multi-dimensional arrays, if you want to preserve your values, you can only increase the last dimension. I.E. Redim Preserve (11,row) or even (11,0) would fail.