npm install express -g的问题

C:\Users\lian_>npm install express -g
npm ERR! code EPERM
npm ERR! syscall mkdir
npm ERR! path C:\Program Files\nodejs\node_cache\_cacache
npm ERR! errno -4048
npm ERR! Error: EPERM: operation not permitted, mkdir ‘C:\Program Files\nodejs\node_cache\_cacache‘
npm ERR!  [OperationalError: EPERM: operation not permitted, mkdir ‘C:\Program Files\nodejs\node_cache\_cacache‘] {
npm ERR!   cause: [Error: EPERM: operation not permitted, mkdir ‘C:\Program Files\nodejs\node_cache\_cacache‘] {
npm ERR!     errno: -4048,
npm ERR!     code: ‘EPERM‘,
npm ERR!     syscall: ‘mkdir‘,
npm ERR!     path: ‘C:\\Program Files\\nodejs\\node_cache\\_cacache‘
npm ERR!   },
npm ERR!   isOperational: true,
npm ERR!   errno: -4048,
npm ERR!   code: ‘EPERM‘,
npm ERR!   syscall: ‘mkdir‘,
npm ERR!   path: ‘C:\\Program Files\\nodejs\\node_cache\\_cacache‘
npm ERR! }
npm ERR!
npm ERR! The operation was rejected by your operating system.
npm ERR! It‘s possible that the file was already in use (by a text editor or antivirus),
npm ERR! or that you lack permissions to access it.
npm ERR!
npm ERR! If you believe this might be a permissions issue, please double-check the
npm ERR! permissions of the file and its containing directories, or try running
npm ERR! the command again as root/Administrator.