Can't place any blocks but break every block

I Started using Bukkit Today with no Plugins to see if it even works and i joined my server gave me OP and tried to place blocks but it simply wouldn't let me place anything. The only thing i could do was break blocks but nothing else. I have spawn-protection in the server.properties file set to 0 and i still cant place anything. The only file in my Plugins folder is the PluginMetrics which it generated automatically.