Error when running npm install for Spark

I followed the "Installation Via Composer" route to install Spark in my barebones Laravel app. This seemed to work fine, until I got to the stage when I had to run npm install. Most of the dependencies seemed to install, but then I got this error:

npm ERR! Windows_NT 6.3.9600
npm ERR! argv "C:\\Program Files\\nodejs\\node.exe" "c:\\Users\\username\\AppData\\Roaming\\npm\\node_modules\\npm\\bin\\npm-cli.js" "install"
npm ERR! node v6.9.1
npm ERR! npm  v2.11.3
npm ERR! path C:\Users\username\AppData\Roaming\npm-cache\wrappy\1.0.2\package\package.json.265819b6836266bbe9863009d238847b
npm ERR! code EPERM
npm ERR! errno -4048
npm ERR! syscall rename

npm ERR! Error: EPERM: operation not permitted, rename 'C:\Users\username\AppData\Roaming\npm-cache\wrappy\1.0.2\package\package.json.265819b6836266bbe9863009d238847b' -> 'C:\Users\username\AppData\Roaming\npm-cache\wrappy\1.0.2\package\package.json'
npm ERR!     at Error (native)
npm ERR!  { Error: EPERM: operation not permitted, rename 'C:\Users\username\AppData\Roaming\npm-cache\wrappy\1.0.2\package\package.json.265819b6836266bbe9863009d238847b' -> 'C:\Users\username\AppData\Roaming\npm-cache\wrappy\1.0.2\package\package.json'
npm ERR!     at Error (native)
npm ERR!   errno: -4048,
npm ERR!   code: 'EPERM',
npm ERR!   syscall: 'rename',
npm ERR!   path: 'C:\\Users\\username\\AppData\\Roaming\\npm-cache\\wrappy\\1.0.2\\package\\package.json.265819b6836266bbe9863009d238847b',
npm ERR!   dest: 'C:\\Users\\username\\AppData\\Roaming\\npm-cache\\wrappy\\1.0.2\\package\\package.json',
npm ERR!   parent: 'once' }

Does anyone know what went wrong here?