Error : Cannot find module 'internal/fs'

when add android platform that time following error is occurring
E:\Shivani\IonicPrograms\TeachersApp>ionic platform add android
Error: Cannot find module 'internal/fs’
at Function.Module._resolveFilename (module.js:470:15)
at Function.Module._load (module.js:418:25)
at Module.require (module.js:498:17)
at require (internal/module.js:20:19)
at evalmachine.:18:20
at Object. (C:\Users\TECH9TEEN-1\AppData\Roaming\npm\node_modules\cordova\node_modules\npm\node_modules\graceful-fs\fs.js:11:8)
at Module._compile (module.js:571:32)
at Object.Module._extensions…js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)

Remove your node modules and then reinstall it.
Then you can give a try adding ionic platform add android