hmmm... from your code I bet the entries into the list box are not quite what you are expecting...
Code:
If Left(sNextLine, 6) = "ALARM=" Then
  List1.AddItem sNextLine
  Redim Preserve MyArray(List1.ListCount) As String
  MyArray(List1.ListCount) = sNextLine
Else
  MyArray(List1.ListCount) = MyArray(List1.ListCount) & sNextLine
End If
Then...
Code:
Private Sub List1_Click()
Dim ForLoopCounter As Integer
For ForLoopCounter = 0 To List1.ListCount - 1
  If List1.Selected(ForLoopCounter) = True Then
    Text1.Text = MyArray(ForLoopCounter + 1)
    Exit For
  End If
Next ForLoopCounter
End Sub


Good Luck