Previously, I received a runtime error '9': Subscript out of range. Now I
get a runtime error '1004': Unable to set the Visible property of the
Worksheet class at
Sheets(sSName).Visible = True
in the code below.

Does anyone have an idea of what other causes there could be?

Perhaps someone could design a workbook and see if the result is the same.
The instructions are at
http://exceltips.vitalnews.com/Pages...by_User.htm l.

Dim bOK2Use As Boolean

Private Sub btnOK_Click()
Dim bError As Boolean
Dim sSName As String
Dim p As DocumentProperty
Dim bSetIt As Boolean

bOK2Use = False
bError = True
If Len(txtUser.Text) 0 And Len(txtPass.Text) 0 Then
bError = False
Select Case txtUser.Text
Case "Austin"
sSName = "Corp"
If txtPass.Text < "u1pass" Then bError = True
Case "Tejas"
sSName = "Elect"
If txtPass.Text < "u2pass" Then bError = True
Case Else
bError = True
End Select
End If
If bError Then
MsgBox "Invalid User Name or Password"
Else
'Set document property
bSetIt = False
For Each p In ActiveWorkbook.CustomDocumentProperties
If p.Name = "auth" Then
p.Value = sSName
bSetIt = True
Exit For
End If
Next p
If Not bSetIt Then
ActiveWorkbook.CustomDocumentProperties.Add _
Name:="auth", LinkToContent:=False, _
Type:=msoPropertyTypeString, Value:=sSName
End If

Sheets(sSName).Visible = True
Sheets(sSName).Unprotect (txtPass.Text)
Sheets(sSName).Activate

bOK2Use = True
Unload UserForm1
End If
End Sub

Private Sub UserForm_Terminate()
If Not bOK2Use Then
ActiveWorkbook.Close (False)
End If
End Sub