Run time errors (52, 76) men ikke på alle computere

Her er den kode der køres for at
1. se om filen allerede er åben
2. finde filnavnet ud fra hele stien
3. åbne filen, hvis den er lukket og ellers blot aktivere vinduet

Problemet er: "some other problem accessing the file".


' This function checks to see if a file is open or not. If the file is
' already open, it returns True. If the file is not open, it returns
' False. Otherwise, a run-time error occurs because there is
' some other problem accessing the file.

Function IsFileOpen(filename As String)
    Dim filenum As Integer, errnum As Integer

    On Error Resume Next  ' Turn error checking off.
    filenum = FreeFile()  ' Get a free file number.
    ' Attempt to open the file and lock it.
    Open filename For Input Lock Read As #filenum
    Close filenum          ' Close the file.
    errnum = Err          ' Save the error number that occurred.
    On Error GoTo 0        ' Turn error checking back on.

    ' Check to see which error occurred.
    Select Case errnum

        ' No error occurred.
        ' File is NOT already open by another user.
        Case 0
        IsFileOpen = False

        ' Error number for "Permission Denied."
        ' File is already opened by another user.
        Case 70
            IsFileOpen = True

        ' Another error occurred.
        Case Else
            Error errnum
    End Select

End Function




Function filnavn(str)
    filnavn = Mid(str, InStrRev(str, "\") + 1, Len(str))
End Function




Public Sub checkindsatsfelter()

'Se om filen med indsatsfelter allerede ER åben, så åbn ikke igen. Ellers åbn.

Dim indsatsfelterfil As String
indsatsfelterfil = Sheets("Opsætning").Range("C6").Value

    If IsFileOpen(indsatsfelterfil) Then
    Windows(filnavn(indsatsfelterfil)).Activate
    Else
    Workbooks.Open (indsatsfelterfil)
    End If

End Sub

lukkes