You can use the Greenfoot sound class to play, pause, stop and do more with a sound. Check the API http://www.greenfoot.org/files/javadoc/greenfoot/GreenfootSound.html
@Kirito101, please show how you are trying to use those method, including what you are calling those methods on (include how you came about what you are calling them on also). NOTE: click on the 'Posting code? read this!' link below the 'Post a reply' input box before posting any code.