xbox music mixer

[ripken204]

i just got the xbox music mixer in hope to put all of my mp3's to my xbox to listen to them during games and to play on my stereo system

i can transfer jpeg's and wma's fine but with an mp3 i get the error

some of the media you selected was invalid

i googled it and only 2 sites came up, one of them said that you should just convert the mp3's to wma and then transer them b/c all that happens with ur mp3's is that they are converted into wma anyways

does any1 know if this is true and should i just convert to wma?