One of 2 things has happened. Either your DVD drive is starting to play up, or you have dirt and/or a scratch on the disc which is preventing the data from being copied correctly.
First thing to do would be to try cleaning the disk, starting from the hole in the middle and going out towards the edge in a straight line. Do not use circular motions, as this can cause scratches in the direction that the data is written, and further stuff up the disk. Use a very soft cloth to do this, do not use any paper based product as they are quite abrasive.
You can also use your product key to download a copty of the game from EA's online store without having to pay extra. Get a copy of EADM (EA download manager), punch in your product code, and you're good to go. Link here;
http://www.ea.com/1/download-manager