Can you update to the latest tweak of unifieddyes? It now requires the user to craft some glass bottles to hold the dyes. I split those off into a separate mod, "Vessels" (
http://minetest.net/forum/viewtopic.php?id=2574), so you'll need both. It's a good idea to return the empty bottles to the player when a dye is used (using the "replacements = XXXX" argument, with "vessels:glass_bottle"). Otherwise you'll waste glass. :-)