Many thanks drlucky - that was very helpful.
I looked at the file types in my iTunes folder. Some were described as MPEG Layer 3 Audio, others were described as MPEG Layer 4 Audio.
I copied and pasted 2 albums of the MPEG Layer 3 Audio type to my sansa clip + without any problems. I copied a 3rd album of the MPEG Layer 4 Audio type as well. That *seemed*to go in okay, except that the name of the artist did not appear, nor did the name of the album. When I played the sansa clip + only the first 2 albums were showing. The 3rd album wasn’t there.
I’m guessing I will need to set up a separate thread about getting these MPEG Layer 4 Audio files into the sansa clip plus. Presumably the first lot were MP3s, and the final album had songs that were not…