VB application stops generating spreadsheet at row 65536

Hello
I have a VB application that's been running for the last couple of years on a machine that has Office 2010 installed. Now that the number of rows generated in the spreadsheet is > 65536, the application stops at this point.

I can't work out why this is happening, the reference used is Microsoft Excel 14.0 Object library.

Here's a snippet of the code, if any more is required, please let me know:

Dim oXL As Excel.Application
Dim oWB As Excel.Workbook
Dim oSheet As Excel.Worksheet

    Set oXL = CreateObject("Excel.Application")
    oXL.Application.Visible = True
      
' Get a new workbook and sheet
    Set oWB = oXL.Workbooks.Add
    Set oSheet = oWB.ActiveSheet

Does anyone know why this is happening? Any help would be greatly appreciated.

Thank you.