Ditto on the replacement of the line. Compression fittings are only good for small water lines around the house, or for connecting mechanical gauges on your car.
Buy the pre-flared tubing at NAPA, and put a new piece in there. They sell it in various lengths up to 40". If you need a longer piece just join them together with brass inverted flare female connectors. You always need a double flared piece of steel tubing for brake lines, and the ones from NAPA are that way. If you buy un-flared tubing or cut a piece, you will need a double flare tubing kit to flare your own.