Are they from CDs? All the music I have on my 810's SD card and on my 920 are also iTunes stuff I have on my iPod. Do you have the original versions of the songs? I find that I have no issues with adding music as long as it wasn't directly acquired from iTunes (though this shouldn't be your issue based on what you say) and can get anything I imported from CDs or mp3s with no problem. Do you use the drag and drop method? That has always worked for me.