I think the problem is you, the Endless, has not (enough of) the required Gems/Ores for that kind of Enchantment you wish to add on one of your equipment items !
And IF an enchantment is selected by the Enchanter "Dreavan" (the NPC by the Wishing Well wink ) when you have choose to Enchant something, all Enchantments are written in "grey" when you don't have the required Gems/Ores !


On 7th of february 2015 : I start a new adventure in the Divinity world of Original Sin,
it's a Fantastic Freaking Fabulous Funny ... it's my All Time Favorite One !