我已经下载了最新版本的mongodb，并将文件移动到mongodb并重命名为目录usr/local/mongodb.当我try 运行mongod时，我得到了以下错误
`./bin/mongod --help` for help and startup options
Sun Apr 15 18:08:25 [initandlisten] MongoDB starting : pid=8801 port=27017 dbpath=/data/db/ 64-bit host=Hanss-MacBook-Air.local
Sun Apr 15 18:08:25 [initandlisten] db version v2.0.4, pdfile version 4.5
Sun Apr 15 18:08:25 [initandlisten] git version: 329f3c47fe8136c03392c8f0e548506cb21f8ebf
Sun Apr 15 18:08:25 [initandlisten] build info: Darwin erh2.10gen.cc 9.8.0 Darwin Kernel Version 9.8.0: Wed Jul 15 16:55:01 PDT 2009; root:xnu-1228.15.4~1/RELEASE_I386 i386 BOOST_LIB_VERSION=1_40
Sun Apr 15 18:08:25 [initandlisten] options: {}
Sun Apr 15 18:08:25 [initandlisten] exception in initAndListen: 10309 Unable to create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?, terminating
Sun Apr 15 18:08:25 dbexit:
Sun Apr 15 18:08:25 [initandlisten] shutdown: going to close listening sockets...
Sun Apr 15 18:08:25 [initandlisten] shutdown: going to flush diaglog...
Sun Apr 15 18:08:25 [initandlisten] shutdown: going to close sockets...
Sun Apr 15 18:08:25 [initandlisten] shutdown: waiting for fs preallocator...
Sun Apr 15 18:08:25 [initandlisten] shutdown: lock for final commit...
Sun Apr 15 18:08:25 [initandlisten] shutdown: final commit...
Sun Apr 15 18:08:25 [initandlisten] shutdown: closing all files...
Sun Apr 15 18:08:25 [initandlisten] closeAllFiles() finished
Sun Apr 15 18:08:25 [initandlisten] shutdown: removing fs lock...
Sun Apr 15 18:08:25 [initandlisten] couldn't remove fs lock errno:9 Bad file descriptor
Sun Apr 15 18:08:25 dbexit: really exiting now