[ubuntu] Something is wrong with my Update Manager (Red Exclamation Mark)

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http://ubuntuforums.org – I have some problem with my Update Manager. When I check for updates, it gives this message: Failed to download repository information, Check internet connection. However, it often does have updates and will download them. This also comes with a couple other problems. One is a red exclamation-triangle in the bar near the top right corner that claims that some of the update information is outdated. The other is in the main Update Manager window, there is a message that says "The package information was last updated 51 days ago." How can I fix this? I think that it is s (Hardware)