Bow Assassin could not learn skill???

[yabushi1992]

Hi guys, I just started a new character this morning (bow assassin). Reached 29lvl, bought 24lvl skill book to learn both my basic sub skill (Strong eyesight) and attack skill, I right clicked it but it doesn't allow me to learn, ''Your position is not suitable for this equipment'' kept poping up. Why? It is so weird I have never encounter this before. Thanks.