after a while, here's the modified solution code:
----------

'http://excel.tips.net/Pages/
T003148_Importing_Multiple_Files_to_a_Single_Workb ook.html

Sub CombineTextFiles()
Dim FilesToOpen
Dim x As Integer
Dim wkbAll As Workbook
Dim wkbTemp As Workbook
Dim sDelimiter As String

On Error GoTo ErrHandler
Application.ScreenUpdating = False

sDelimiter = "|"

FilesToOpen = Application.GetOpenFilename _
(FileFilter:="Text Files (*.txt), *.txt", _
MultiSelect:=True, Title:="Text Files to Open")

If TypeName(FilesToOpen) = "Boolean" Then
MsgBox "No Files were selected"
GoTo ExitHandler
End If

x = 1
' Set wkbTemp = Workbooks.Open(Filename:=FilesToOpen(x)) *** below is
forced text format

Set wkbTemp = Workbooks.Open(Filename:=FilesToOpen(x),
Format:=xlTextFormat)


wkbTemp.Sheets(1).Copy
Set wkbAll = ActiveWorkbook
wkbTemp.Close (False)
wkbAll.Worksheets(x).Columns("A:A").TextToColumns , _
Destination:=Range("A1"), DataType:=xlDelimited, _
TextQualifier:= _
xlNone, ConsecutiveDelimiter:=False, Tab:=True,
Semicolon:=False, Comma _
:=False, Space:=False, Other:=False, OtherChar:="|", _
FieldInfo:=Array(Array(1, 2), Array(2, 2), Array(3, 2), Array(4, 2),
Array(5, 2), Array(6, 2), Array(7, 2), Array(8, 2), Array(9, 2),
Array(10, 2), Array(11, 2), Array(12, 2), Array(13, 2), Array(14, 2),
Array(15, 2), Array(16, 2), Array(17, 2), Array(18, 2), Array(19, 2),
Array(20, 2), Array(21, 2), Array(22, 2), Array(23, 2), Array(24, 2),
Array(25, 2), Array(26, 2), Array(27, 2), Array(28, 2), Array(29, 2),
Array(30, 2), Array(31, 1), Array(32, 1), Array(33, 1), Array(34, 1),
Array(35, 1), Array(36, 1), Array(37, 1), Array(38, 1), Array(39, 1),
Array(40, 1), Array(41, 9))

' **** array forcing text format (2)



x = x + 1

While x <= UBound(FilesToOpen)
Set wkbTemp = Workbooks.Open(Filename:=FilesToOpen(x))
With wkbAll
wkbTemp.Sheets(1).Move After:=.Sheets(.Sheets.Count)
wkbAll.Worksheets(x).Columns("A:A").TextToColumns , _
Destination:=Range("A1"), DataType:=xlDelimited, _
TextQualifier:= _
xlNone, ConsecutiveDelimiter:=False, Tab:=True,
Semicolon:=False, Comma _
:=False, Space:=False, Other:=False, OtherChar:="|", _
FieldInfo:=Array(Array(1, 2), Array(2, 2), Array(3, 2), Array(4, 2),
Array(5, 2), Array(6, 2), Array(7, 2), Array(8, 2), Array(9, 2),
Array(10, 2), Array(11, 2), Array(12, 2), Array(13, 2), Array(14, 2),
Array(15, 2), Array(16, 2), Array(17, 2), Array(18, 2), Array(19, 2),
Array(20, 2), Array(21, 2), Array(22, 2), Array(23, 2), Array(24, 2),
Array(25, 2), Array(26, 2), Array(27, 2), Array(28, 2), Array(29, 2),
Array(30, 2), Array(31, 1), Array(32, 1), Array(33, 1), Array(34, 1),
Array(35, 1), Array(36, 1), Array(37, 1), Array(38, 1), Array(39, 1),
Array(40, 1), Array(41, 9))

' **** array forcing text format (2) although seems not
necessary


End With
x = x + 1
Wend

ExitHandler:
Application.ScreenUpdating = True
Set wkbAll = Nothing
Set wkbTemp = Nothing
Exit Sub

ErrHandler:
MsgBox Err.Description
Resume ExitHandler
End Sub
----------------------------------------------------