Not able to read polymorph books

Hello guys,

I have a lvl79 warrior and i'm stuck with polymorph skil at 6 because when i try to read the books it says i'm not bale too, anyone know why this bug is happening?

I hope you dont read the wrong books..
Apart from the fact that I have no idea about bug fixes... (if it is a bug)
It would be very helpful to know whether, for example, it is the official server or a P-server (if official then perhaps ask there, if P-server then ask the team?)