I think that's full version only or something like that, because it didn't work for me either.
Doesn't work for me.
Must've downloaded the wrong thing. :c
I found out another way, to get it to work.
Hit esc, and type the hot key of the material you want.
All standard materials can be found here,
http://oecake.wikia.com/wiki/Standard_materialsAlso see,
Mix mode..
Also in mix mode type this in.
xcvbnmasdfghjklpoiuytrewq. (Basically every letter besides "Z" because z is the eraser.)
Then add water.