How come when i try to add music to my video it says this?!?!?

i have windows moviemaker and when i try to add cali girls by katy perry it says this: the duration of the progect can not be more the 24 hours you can trim or clip to reduse there lengh......... its an mp3 download off of Aimini.ne wha could be wrong becauls the song is olny 3 mins. and 55 sec.