Cannot start Enterprise Manager for Weblogic server 11gR1(10.3.6)

I have installed Weblogic server 11gR1 (10.3.6) on Windows 7 32 bit, I created a base_domain as default

and can start weblogic administration server (http://<machine>:7001/console) successfully.

Now I want to use the Oracle Enterprise Manager for Weblogic server by URL http://<machine>:7001/em.

But when I try to access it via a web browser, the following HTTP error is returned:

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Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.