iTunes not syncing certain mp3's

[ckeck]

What would cause iTune's to not sync certain MP3's?

I just recently downloaded a few and added them to my library...consolidated...synced and nothing.

I unchecked one of the songs, synced, checked it, synced again and it worked, but thats not working for one of the others.

Whats the deal? Never seen this happen before

 

[mad jew]

Where'd you get the tracks from? Can you re-rip them? Have you tried using the Advanced Menu to convert them? Sometimes I find this helps, although it can result in a loss of quality. For minimum loss, convert to the same format and bitrate as the original.