Rca mp3 what you do when they come up at "profilling required 20mb free space"?

My Rca mp3 is coming up as "profiling required 20mb free space" I've looked all over the internet trying to figure out how to fix it......can someone help me i mean it doest have to many song on it. it has maybe 350 songs and my sister has 700 songs on hers and no thin is wrong with hers.....how do i fix the problem???? can someone help me please.