Help needed with precious stone

Sry if the answer for my question is on another thread but until now i could't find it...
Question: I have a bukkit sv with precious stone insttaled...the problem is that the diamond block/emerald turns into prot only if you are op or owner...for all the other groups when you place any precious block it remains normal (just decoration, no abbility).
How can i fix this can someone please help me step by step?