I had the exact problem. I was extremely angry when this happened and was afraid I had screwed up my iPod Touch (2G, 16gig) for good! Earlier, before I synced, I had a voice memo on my computer. I tried to rename it or something and then synced my iPod. If this was the case, go on to your iPod and delete the specific voice memo you edited. Then, while your iPod is still connected to your computer, go in to your Music. It will say something like "Updating Library" and then everything will be fixed. It worked for me...