The Skills Hav No Use??????????? L2J

[iko-iki]

Hello!!
pls help. I train myself with some skills. But the problem is that:
when I hit the monster by using skill (ex: power strike) It's no effect. It almost do no damage to that monster. Why?

Did anyone run into it yet? Pls tell me how I can fix it!!!

p.s. Just one more thing: the NPCs dont sell items to me!!!! Why?

 

[Strider-RK]

not sure if it still applies but last time i played it skills werent implemented right yet, and some shopkeeps werent working yet either