Hmm, interesting problem.
I have a scrambled name for the purplish dust that is in all of the energized core recipes.
On the progress tab I have available to do refractory gems (guessing this was supposed to trigger from mining lumenite, based on the lumenite description?), glowing towers, mysterious relics (I haven't found either of these or a luminous cliffs biome, starting to wonder if there's a worldgen conflict with the structure and if the biome is just really rare?), aerial predator (on a server, someone beat me to the dragon), and recharging.
Aside from those, not sure what I'm not doing.
As far as the Dragon being dead, just get your server admin to delete The End dimension folder in the server's world folder (make sure no one is in the end first) and the next time you enter The End it should generate anew and give you the chance to kill the dragon for the achievement.
For the possible biome issue, if you really believe you've looked extensively (I'm talking looked 1000 in a direction or two) then there's an admin way to determine if a biome is present.
DragonAPI adds a /findbiome command you use with the appropriate biome ID and it'll list the coords of the biomes. To get the biome IDs just use NEI's Data Dump feature for biomes and it'll dump a list of biomes into your client's minecraft folder (see http://ftb.gamepedia.com/NEI#Dumps)