Maya does not read _ in image sequences your files need to be named like so
"filename.#.ext"
this will not work "filename_#.ext" nor will this sometimes "file.name.#.ext" maya is real picky
stick with filename.#.ext
From a readers' Q and A column in TV GUIDE: "If we get involved in a nuclear war, would the electromagnetic pulses from exploding bombs damage my videotapes?"