excel – Compile Error: Next without For

It is not the problem of For/Next Loop.

Change the line

ErrHandler: If Err.Number = 1004 Then

to

ErrHandler: If Err.Number = 1004 Then

TIP: Always indent your code 🙂 You might also want to see this (point 4)?

EDIT: See Point 6 in the above link as well 🙂 To illustrate that in your code, see this part

    Set appExcel = Nothing
    Set wkb = Nothing
    Set wks = Nothing
    Set rng = Nothing
    Set msg = Nothing
    Set nms = Nothing
    Set fld = Nothing
    Set itm = Nothing
    Exit Sub
 ErrHandler:
    If Err.Number = 1004 Then
        MsgBox strSheet & " doesn't exist", vbOKOnly, "Error"
    Else
        MsgBox Err.Number & "; Description: ", vbOKOnly, "Error"
    End If

    Set appExcel = Nothing
    Set wkb = Nothing
    Set wks = Nothing
    Set rng = Nothing
    Set msg = Nothing
    Set nms = Nothing
    Set fld = Nothing
    Set itm = Nothing
End Sub

This can be also written as

LetsContinue:
    Set appExcel = Nothing
    Set wkb = Nothing
    Set wks = Nothing
    Set rng = Nothing
    Set msg = Nothing
    Set nms = Nothing
    Set fld = Nothing
    Set itm = Nothing
    Exit Sub
ErrHandler:
    If Err.Number = 1004 Then
        MsgBox strSheet & " doesn't exist", vbOKOnly, "Error"
    Else
        MsgBox Err.Number & "; Description: ", vbOKOnly, "Error"
    End If

    Resume LetsContinue
End Sub

Another example

If fld Is Nothing Then
    MsgBox "There are no mail messages to export", vbOKOnly, "Error"
    Exit Sub
ElseIf fld.DefaultItemType <> olMailItem Then
    MsgBox "There are no mail messages to export", vbOKOnly, "Error"
    Exit Sub
ElseIf fld.Items.Count = 0 Then
    MsgBox "There are no mail messages to export", vbOKOnly, "Error"
    Exit Sub
End If 'Open and activate Excel workbook. Set appExcel = CreateObject("Excel.Application")

Set wkb = appExcel.Workbooks.Open(strSheet)
Set wks = wkb.Sheets(1)
wks.Activate

You don’t need to use Exit Sub so many times

You can put the rest of the code in the Else part of the IF

In fact DO NOT use Exit Sub at all in your code. Reason being, your code will exit the sub without destroying and cleaning up the objects that you created. Exit the procedure gracefully 🙂

FOLLOWUP

Try this code. (UNTESTED)

Sub ExportToExcel()
    On Error GoTo ErrHandler

    '~~> Excel Objects / Variables
    Dim appExcel As Excel.Application
    Dim wkb As Excel.Workbook
    Dim wks As Excel.Worksheet

    Dim strSheet As String, strPath As String
    Dim intRowCounter As Long, intColumnCounter As Long

    '~~> Outlook Objects
    Dim msg As Outlook.MailItem
    Dim nms As Outlook.Namespace
    Dim fld As Outlook.MAPIFolder
    Dim itm As Object

    strSheet = "OutlookItems.xls"
    strPath = "C:\"

    strSheet = strPath & strSheet

    Set nms = Application.GetNamespace("MAPI")
    Set fld = nms.PickFolder

    If fld Is Nothing Then
        MsgBox "There are no mail messages to export", vbOKOnly, "Error"
    ElseIf fld.DefaultItemType <> olMailItem Then
        MsgBox "There are no mail messages to export", vbOKOnly, "Error"
    ElseIf fld.Items.Count = 0 Then
        MsgBox "There are no mail messages to export", vbOKOnly, "Error"
    Else
        'Open and activate Excel workbook.
        Set appExcel = CreateObject("Excel.Application")

        Set wkb = appExcel.Workbooks.Open(strSheet)
        Set wks = wkb.Sheets(1)
        appExcel.Visible = True

        'Copy field items in mail folder.
        For Each itm In fld.Items
            Set msg = itm

            With wks
                intRowCounter = intRowCounter + 1
                .Cells(intRowCounter, intColumnCounter) = msg.To

                intColumnCounter = intColumnCounter + 1
                .Cells(intRowCounter, intColumnCounter) = msg.SenderEmailAddress

                intColumnCounter = intColumnCounter + 1
                .Cells(intRowCounter, intColumnCounter) = msg.Subject

                intColumnCounter = intColumnCounter + 1
                .Cells(intRowCounter, intColumnCounter) = msg.Body

                intColumnCounter = intColumnCounter + 1
                .Cells(intRowCounter, intColumnCounter) = msg.SentOn

                intColumnCounter = intColumnCounter + 1
                .Cells(intRowCounter, intColumnCounter) = msg.ReceivedTime
            End With
        Next itm
    End If
LetsContinue:
    Set appExcel = Nothing
    Set wkb = Nothing
    Set wks = Nothing
    Set msg = Nothing
    Set nms = Nothing
    Set fld = Nothing
    Set itm = Nothing
    Exit Sub
ErrHandler:
    If Err.Number = 1004 Then
        MsgBox strSheet & " doesn't exist", vbOKOnly, "Error"
    Else
        MsgBox "Error Number: " & Err.Number & vbNewLine & _
               "Error Description: " & Err.Description, vbOKOnly, "Error"
    End If
    Resume LetsContinue
End Sub

Assuming your code looks like what you pasted, the reason you are getting the error is this line:

'Copy field items in mail folder. For Each itm In fld.Items 

Notice that the for part of your loop is part of your comment?

Siddharth gave you a lot of good tips to help avoid these kind of problems, but to get your code to compile just replace the line I showed you with this:

'Copy field items in mail folder. For Each itm In fld.Items 

You also commented out another line:

'Select export folder Set nms = Application.GetNamespace("MAPI")

Should be:

'Select export folder Set nms = Application.GetNamespace("MAPI")