Bukkit

I have a small problem:

Yesterday I destroyed some blocks to see if everything works fine. And yes, it did.

But today I'm trying to right-click and left-click on a position where an item was placed and destroyed. The placed item isn't recognized by the system anymore, I'm only getting the message: „Information about this block is no longer available.“

If I left-click the block I've placed this message appears every time. Only on the block I've destroyed this message appears sometimes.

Don't know what the problem could be, hope to get some help.

Ah and btw: I'm using a Bukkit Version of MCPC+, it's version 1.6.4-R2.1 || Also I hope this is the right section for my request now :/.