[iTunes] Shuffle Problems

[Bob Warner]

  I can't transfer some podcasts and music to my Shuffle. I keep  
getting the error message:

<Some of the songs in the iTunes music library, including the song  
"SONG OR PODCAST NAME", were not copied to the iPod "Robert Warner"s  
iPod" because they cannot be played on this iPod.>

I have read all the Apple support bulletins and have tried  
everything! Nothing appears to solve the problem.

At the moment, the answer appears to be there ain't no answer. It  
seems that some podcasts and music can be transferred to my Shuffle.  
Others can't.

Any ideas (please be aware that I HAVE read and tried everything  
Apple has suggested)?

Many thanks!