Ipod touch and limewire/itunes

Help! I was able to transfer my limewire files to itunes, then from itunes to my ipod touch until yesterday. I am still able to transfer the file to itunes, however, now when my ipod syncs it does not add the new files to my ipod anymore! My husband did download some of my files to an MP3 player and the next time I tried to sync to my ipod after that it did not work. Any advice would be greatly appreciated!!