What if i overflows: either an overflow error and a crash, or it resets to 0 or a large negative number if it's a signed int. Whichever way that...
You are on online-mode=true aren't you?
Linux-based OS'es can be faster, but if you've never used them you'd be much better off sticking with Windows.
Oh and leave server-ip= blank in server.properties
put online-mode=true in server.properties
PLEASE read about SQL injection before you deploy that code!
To rollback TNT amd other griefing, you need a logging plugin such as BigBrother, HawkEye or LogBlock, although I'm not sure which ones are still...
Separate names with a comma.