title: OpenOPC on Windows: Clas not registered
body: <p>I'm having problems with OpenOPC library (OpenOPC-1.2.0.win32-py2.7) on Windows 7 64bit machine.</p>
  
  <pre><code>&gt;&gt;&gt; import OpenOPC
  &gt;&gt;&gt; i =OpenOPC.client()
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "OpenOPC.py", line 170, in __init__
      raise OPCError, error_msg
  OpenOPC.OPCError: Dispatch: Class not registered.
  </code></pre>
  
  <p>What could be the cause of this error? My command line opc client works fine.</p>