この Web ブラウザーでは、証明書要求の生成がサポートされていません" というエラーがInternet Explorer

'
' If there is no '.' in the UserAgent string, this will return the next character if any
' as the version number. ' We extract the string until a '.' and then convert it
' into integer. If -1 is returned from this function then it isn't MSIE 
'
Function GetInternetExplorerVersionNumber(sHttpUserAgent)
    Dim nMSIE

GetInternetExplorerVersionNumber = -1     nMSIE = InStr(sHttpUserAgent, "MSIE")

    If 0 <> nMSIE Then

        numChar = InStr(Mid(sHttpUserAgent, nMSIE + 5), ".") - 1

        If -1 = numChar Then ' no '.' in the string
           numChar = 1
        End If

        If nMSIE + 5 + numChar - 1 <= Len(sHttpUserAgent) Then
            GetInternetExplorerVersionNumber = CInt(Mid(sHttpUserAgent, nMSIE + 5, numChar))
        End If 
    End If

End Function

'
' We define a Old MSIE based browser
' if it has the string MSIE that is followed by a version number that is less than 4
' NOTE:
' IsOldMSIE = False does not imply MSIE >= 4.
'
' i.e. Not IsOldMSIE("abc") = True
'      Not IsOldMSIE("MSIE") = True
'

Function IsOldMSIE(sHttpUserAgent)
   Dim nMSIE
   Dim sMSIEVersion

   IsOldMSIE = False

   nMSIE = InStr(sHttpUserAgent, "MSIE")

   If nMSIE <> 0 AND (nMSIE+5 < Len(sHttpUserAgent)) Then
      nVersion = GetInternetExplorerVersionNumber(sHttpUserAgent)
      If -1 <> nVersion Then
          IsOldMSIE = nVersion < NEW_MSIE_VERSION
      End If
   End If

End Function

'
' We define a Old MSIE based browser
' if it has the string MSIE that is followed by a version number that is less than 4
' NOTE:
' IsOldMSIE = False does not imply MSIE >= 4.
'
' i.e. Not IsOldMSIE("abc") = True
'      Not IsOldMSIE("MSIE") = True
'
Function IsOldMSIE(sHttpUserAgent)
   Dim nMSIE
   Dim sMSIEVersion

   nMSIE = InStr(sHttpUserAgent, "MSIE")

   If nMSIE=0 Then
      IsOldMSIE = False

   ElseIf nMSIE+5 < Len(sHttpUserAgent) Then
      sMSIEVersion = Mid(sHttpUserAgent, nMSIE+5, 1)
      IsOldMSIE = CInt(sMSIEVersion) < NEW_MSIE_VERSION

   Else
      IsOldMSIE = False
   End If

End Function