[ubuntu] 12.04 "Failed to load package list" error

view story

http://ubuntuforums.org – I'm newish to ubuntu, or at least not learning very fast. Today an icon of a red circle with a white bar through it tells me to check Package Manager. It also tells me the error is "serious". I have no problems otherwise. The error message is: E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_precise_main_i1 8n_Translation-en, E:The package lists or status file could not be parsed or opened. Package Manager says the same thing. Should I be worried? (Hardware)