'Unexpected White Concrete' error when I try to fill with white concrete?

Solution 1:

The issue you are encountering is that there is no block called "white concrete" in commands. You have to put concrete, followed by the data tag that corresponds to the colour white.

/fill x y z x2 y2 z2 concrete 0

The above command would fill the area with white concrete, because 0 is the data tag for white in the case of concrete (you could also just omit the 0, because white is the default colour of concrete when using /fill).

I have a picture of all the data tags for the different colours of concrete, but for some reason they wont attach to this post.

Here's a link to the wiki page where I found them instead.