RSS viewer web part issue

I’m getting following error message:

[strong] ”ProtocolError occured trying to complete the request. The server returned a status code of : InternalServerError and the status description is : ‘Internal Server Error’” [/strong]

When I try to use RSS viewer web part with following RSS Feed URL:

[strong]http://apps.shareholder.com/rss/rss.aspx?channels=5336&companyid=CEG&sh_auth=1043879954%2E0%2E0%2E11580d4f23d70bc672045d636ac34f53[/strong]

Above rss feed url works fine with IE feeds/Firefox Live bookmark and Outlook rss feeds.