I tried to craft some Illumar today, it just worked once and now i can't craft any of them. I still see the crafting-recept in NEI. I tried it in my Single Player World, to check if something is wrong with my client, but nope it worked fine there. Screenshots
This is the case with some crafting recipes but I may be incorrect for this problem. Try placing it exactly how the recipe says, as in top left corner.
Yea i crafted a green one and just couldn't craft more, I even had enough materials in the slot to craft a few of them.
Hmm.. Strange, this is all I can suggest at the moment. Make sure you actually received the original crafted item and that it hasn't visually glitched out. Try getting more of the cactus green and glowstone dust to make it. Use another Crafting table.
I found the problem it seems like i used glowstone dust made out of chiseled glowstones, which i mixed with my normal glowstone dust, so that the dust had a different ID (348:3). Thanks for your help!