[X4U] can't copy to ipod

[Mitchell Senft]

Tried copying an mp3, an mp4 as well as the iPod version of Apple's  
iPhone video. All resulted in this message:

""{Such and such" was not copied to the iPod... because it cannot be  
played on this iPod.""

As a brief test, I copied a track downloaded from the iTunes store  
onto the iPod -- no problem.

So why all of a sudden did it turn all tricky? And I had just  
transfered a number of CDs to it without a problem.

The Mac is a G5, OS X 10.9, iTunes 7.1. The iPod is current to my  
knowledge ("first" 5G 30G iPod). Since the problem, I did a soft  
reset; haven't tried transfering again since so if that's the  
solution, don't know. But if that isn't, why the problem, what's the  
solution?

Thanks,
Mitchell