I had this one MP3 a PC user sent me that gave me an error any time I tried to do anything to it other than play it (convert it AIFF, burn it, etc.). I decided that fixing it wasn't worth it so I groaned and took out the CD and ripped it from the CD instead. With my DSL and my friends DSL, we can get pretty good speeds, so if he has an MP3 of a song, I'll ask him if he could send it to me, because its MUCH more trouble (esp. on a beige G3) to have the comp churn and make an MP3 file than to get it sent to me.
In other words, just find the offending song and make a fresh copy from the CD (you do
have the CD, don't you?
). I had an error kind of like that and it worked for me.