When validating a stylesheet importing a print / embossed stylesheet:
@import url("print.css") print, embossed;

the validator gives strange errors in the linked print.css stylesheet, for example:
Color property always produces the error "Invalid number : color[color] is not a
color value : [color]"
Background property always produces the error "Invalid number :
background[color]Too many values or values are not recognized : [color]"
Border-bottom property always produces the error "Invalid number :
border-bottomParse Error - [empty string]"

You can see this bug in action by following this link:
http://jigsaw.w3.org/css-validator/validator?uri=http%3A%2F%2Fgraceful.port5.com%2Fstyle%2Fbasic.css&profile=css2