Why can't I open my private chests in Minecraft? Pixelmon server?

(I believe the server has bukkit but I'm not sure.)

I placed a private sign with mine and a friend's name on it, and now I can't destroy or access the chest. It claims that it is his chest, though he can't destroy the sign or chest either. The server runs pixelmon if that changes anything. IP: play.pmunleashed.net

Hm, this is new. Can't really help you solve the problem. But try this fix. Attach a hopper below the chest to another chest. If the server has not patched this, your items should start draining out to the next chest.