Go to this link.
imobilecinema help??
This is the solution and has worked for me and friends.
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If you don't want to read the link do this
You can ssh into your phone and remove the entry from the "/private/etc/apt/sources.list.d\cydia.lst" and also remove it from the "/private/var/lib/apt/lists". And I also remove it from the "/private/var/lib/apt/lists/partial" if it shows ther as well. Sometimes you have to delete the "Lock" file and refresh the library and then it will show. Give this a try to remove the link from Cydia.
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This is not just for imobile cinema but any source you get errors from