I Need Some Help On Something.. ^^;

[Lord_Examinis]

..Well, I got these spells, the book looking item in my inventory, but I try to use it, but it wont let me, and I check the levels on what level you need to be to use it, but it only says 'above 16' and I'm 17, almost to 18...
So whats the reason? Why can't I use them?

[kioji_Y]

try clicking on it twice

[Kayarine]

Maybe you already have that skill learned? Unless it's a different level (like Lv2 Magic Ice), I don't think you can use the book of a skill you already have.

[Lord_Examinis]

I did click it twice, and it said, "Cannot use the item."

And if so, then how to do not learn the spells, so you can replace them with the new spells?
This is really confusing. :-(