Can't destroy a certain set of blocks in my own region

[Longbow73]

OK, so in Castle Libarez, I had a lava trap for invading mobs and stuff. Well, it was activated by a craftbook bridge, and though the bridge no longer works because it is made of stone brick after an admin transmuted all the cobble in the castle, I cannot destroy the blocks that were affected by the bridge and thus cover the lava. I want to replace those specific ones so I can revive the trap. Can anyone tell me why I cannot break these specific blocks? It's frustrating me to an extreme.