Hi, I have a lens that is about a year old - been using it regularly with no problems. 18mm-250mm with my EOS 50D. All of a sudden it stopped working, I get an error message when I press the shutter button, to check the connection to the camera. I disconnect the lens and wipe it off, put it back in sometimes it would work - but now it doesn't work at all. I tried my other lens on my camera and that is working ok. Help.