Reproduce by npm packing your favorite npm module and then npm install'ing that tarball.
Confirmed and reproduced. Thanks for filing this!
No worries. I should have posted it above, here is the stack trace:
npm ERR! AssertionError: must have callback function
npm ERR! at addTmpTarball (/usr/local/lib/node_modules/npm/lib/cache/add-local-tarball.js:129:3)
npm ERR! at /usr/local/lib/node_modules/npm/lib/cache/add-local-tarball.js:74:9
npm ERR! at Object.oncomplete (fs.js:107:15)