SpatialLines

I'm hoping to use R for spatial analysis.  In working through examples in Chapt. 4 of Applied Spatial Data Analysis with R I've come across the following error in trying to plot lines with the meuse data set.  The text is verbatim from the book.

m.sl <- SpatialLines(list(Lines(list(Line(cc)))))

Error in Lines(list(Line(cc))) : Single ID required

What does "Single ID required" mean?

Thanks.

Mark