Excel 2007 not recognising code built in Excel 2003

Hi

I recently upgraded my Excel from 2003 to 2007 and I am having issues running the below code through Visual Basic which imports data from a closed workbook in my directory to an open workbook. It was working fine in 2003 but since upgrading it seems to no longer recognise it. The problem seems to be when it is finding the file to import the data from and unsure how to fix it. Any help would be greatly appreciated:

Option Explicit
Dim strFileName As String
Dim strCodeBook As String
Dim wbCodeBook As Workbook

Public Sub RunCodeOnAllXLSFiles()

Dim lCount As Long
Dim wbResults As Workbook


Application.ScreenUpdating = False
Application.DisplayAlerts = False
Application.EnableEvents = False

On Error Resume Next

Set wbCodeBook = ThisWorkbook
strCodeBook = wbCodeBook.Name

    With Application.FileSearch
    .NewSearch
         'Change path to suit
    .LookIn = "K:\BIG EUROPE ART\SALES\2011\RFP DATA\Cover Sheets"
    .FileType = msoFileTypeExcelWorkbooks
        '.Filename = "Book*.xlsx"
        
    If .Execute > 0 Then 'Workbooks in folder
    For lCount = 1 To .FoundFiles.Count 'Loop through all.
                 'Open Workbook x and Set a Workbook variable to it
    Set wbResults = Workbooks.Open(Filename:=.FoundFiles(lCount), UpdateLinks:=0)
                                  
    strFileName = wbResults.Name
                                                   
    Call ImportData
                 
    wbResults.Close SaveChanges:=True
             
    Next lCount
    End If
    End With
    
    On Error GoTo 0
    Application.ScreenUpdating = True
    Application.DisplayAlerts = True
    Application.EnableEvents = True
End Sub

Sub ImportData()

''written by rmcniven,maplecourt

''declare variables for data to import
Dim strAccount As String
Dim strAcManager As String
Dim dtDeadline As Date
Dim dtReceived As Date
Dim strSpecial As String
Dim strLRA As String
Dim strCommissionable As String
Dim strCXL As String
Dim strSTDRoomsOnly As String
Dim strAllowSquatters As String
Dim strNumberProperties As String
Dim str3rdPartysite As String
Dim strsite As String
Dim a As Integer

''assign data in cover sheet to variables

Windows(strFileName).Activate

With Sheets("RFPC Instruction Page")
    strAccount = .Cells(5, 4).Value
    strAcManager = .Cells(3, 4).Value
    dtDeadline = .Cells(9, 4).Value
    dtReceived = .Cells(3, 11).Value
    strSpecial = .Cells(65, 3).Value
    strLRA = .Cells(13, 4).Value
    strCXL = .Cells(14, 4).Value
    strCommissionable = .Cells(15, 4).Value
    strSTDRoomsOnly = .Cells(16, 4).Value
    strAllowSquatters = .Cells(60, 4).Value
    strNumberProperties = .Cells(11, 4).Value
    str3rdPartysite = .Cells(33, 8).Value
    strsite = .Cells(36, 8).Value
    
    
End With

''dump data into corresponding cells in consolidation workbook(this one)

wbCodeBook.Activate

Cells(3, 1).Select

For a = 1 To 10000
    If Cells(3 + (a - 1), 1).Value = "" Then
    Exit For
    End If
Next a

Cells(3 + (a - 1), 1).Value = strAccount
Cells(3 + (a - 1), 2).Value = strAcManager
Cells(3 + (a - 1), 4).Value = dtDeadline
Cells(3 + (a - 1), 5).Value = dtReceived
Cells(3 + (a - 1), 7).Value = strSpecial
Cells(3 + (a - 1), 9).Value = strLRA
Cells(3 + (a - 1), 10).Value = strCommissionable
Cells(3 + (a - 1), 11).Value = strCXL
Cells(3 + (a - 1), 12).Value = strSTDRoomsOnly
Cells(3 + (a - 1), 15).Value = strAllowSquatters
Cells(3 + (a - 1), 16).Value = strNumberProperties
Cells(3 + (a - 1), 17).Value = str3rdPartysite
Cells(3 + (a - 1), 18).Value = strsite


End Sub