Can not access Central Admin after install Feb 2012 CU

Hi,

After installing the Feb 2012 CU using the SharePoint install account, then restarting the server and trying to access Central Admin I get this:

The system cannot communicate with the external server ( serverHostname ). The Internet server may be busy, may be permanently down, or may be unreachable because of network problems. 

Please check the spelling of the Internet address entered. If it is correct, try this request later. 

If you have questions, or feel this is an error, please contact your corporate network administrator and provide the codes shown below. 

• What can I do to get to Central Admin? It was all OK before installing this CU

Any ideas?