Excel VBA Code to retrieve e-mails from outlook

To fix your error (olFolderInbox is a Outlook only constant, so you need to define it in vba that is not Outlook):

Const olFolderInbox = 6
'...
Set Fldr = olNs.GetDefaultFolder(olFolderInbox).Folders("PRE Customer")

Also to prevent missing Reference when run from another computer, I would:

Dim olApp As Object
Dim olNs As Object
Dim Fldr As Object
Dim olMail As Object
Dim i As Long
Set olApp = CreateObject("Outlook.Application")
'...

You might also want to disable ScreenUpdating, then enable it in Excel if you expect a long list.

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UPDATE (Solution for all folders from a Root Folder)

I used something slightly different for comparing the dates.

Option Explicit

Private lRow As Long, x As Date, oWS As Worksheet

Sub GetFromInbox()
    Const olFolderInbox = 6
    Dim olApp As Object, olNs As Object
    Dim oRootFldr As Object ' Root folder to start
    Dim lCalcMode As Long

    Set olApp = CreateObject("Outlook.Application")
    Set olNs = olApp.GetNamespace("MAPI")
    Set oRootFldr = olNs.GetDefaultFolder(olFolderInbox).Folders("PRE Customer")
    Set oWS = ActiveSheet

    x = Date
    lRow = 1
    lCalcMode = Application.Calculation
    Application.Calculation = xlCalculationManual
    Application.ScreenUpdating = False
    GetFromFolder oRootFldr
    Application.ScreenUpdating = True
    Application.Calculation = lCalcMode

    Set oWS = Nothing
    Set oRootFldr = Nothing
    Set olNs = Nothing
    Set olApp = Nothing
End Sub

Private Sub GetFromFolder(oFldr As Object)
    Dim oItem As Object, oSubFldr As Object

    ' Process all mail items in this folder
    For Each oItem In oFldr.Items
        If TypeName(oItem) = "MailItem" Then
            With oItem
                If InStr(1, .Subject, "transactions", vbTextCompare) > 0 And DateDiff("d", .ReceivedTime, x) = 0 Then
                    oWS.Cells(lRow, 1).Value = .Subject
                    oWS.Cells(lRow, 2).Value = .ReceivedTime
                    oWS.Cells(lRow, 3).Value = .SenderName
                    lRow = lRow + 1
                End If
            End With
        End If
    Next

    ' Recurse all Subfolders
    For Each oSubFldr In oFldr.Folders
        GetFromFolder oSubFldr
    Next
End Sub

Just loop through all the folders in Inbox.
Something like this would work.

Edit1: This will avoid blank rows.

Sub test()
    Dim olApp As Outlook.Application, olNs As Outlook.Namespace
    Dim olFolder As Outlook.MAPIFolder, olMail As Outlook.MailItem
    Dim eFolder As Outlook.Folder '~~> additional declaration
    Dim i As Long
    Dim x As Date, ws As Worksheet '~~> declare WS variable instead
    Dim lrow As Long '~~> additional declaration

    Set ws = Activesheet '~~> or you can be more explicit using the next line
    'Set ws = Thisworkbook.Sheets("YourTargetSheet")
    Set olApp = New Outlook.Application
    Set olNs = olApp.GetNamespace("MAPI")
    x = Date

    For Each eFolder In olNs.GetDefaultFolder(olFolderInbox).Folders
        'Debug.Print eFolder.Name
        Set olFolder = olNs.GetDefaultFolder(olFolderInbox).Folders(eFolder.Name)
        For i = olFolder.Items.Count To 1 Step -1
            If TypeOf olFolder.Items(i) Is MailItem Then
                Set olMail = olFolder.Items(i)
                If InStr(olMail.Subject, "transactions") > 0 _
                And InStr(olMail.ReceivedTime, x) > 0 Then
                    With ws
                       lrow = .Range("A" & .Rows.Count).End(xlup).Row
                       .Range("A" & lrow).Offset(1,0).value = olMail.Subject
                       .Range("A" & lrow).Offset(1,1).Value = olMail.ReceivedTime
                       .Range("A" & lrow).Offset(1,2).Value = olMail.SenderName
                    End With
                End If
            End If
        Next i
        Set olFolder = Nothing
    Next eFolder
End Sub

Above takes care of all subfolders in Inbox.
Is this what you're trying?