all i can suggest is that you protect it with towny there is a full tutorial on these forums and if you are looking for further help i would be glad to be of assistance, however if you know who the griefer is please talk to me privatley and we shall investigate further into the situation keeping you as anonymous, once you have started a town (/towny prices to check the cost) use the command /t set perm off or /t set perm denyall which will stop outsiders and residents from building/destroying in your town.
Please feel free to talk to me if you require further assistance
ok considering that 1. it's my town and was protected untill towny crashed, 2. sir was the one who posted the first complete towny command guide, and 3. an op or admin is needed to find who griefed a said town, this response has little relevance to the situation lol. mews this situation has been atm resolved~