yarn@0.16.1 fails with "TypeError: Cannot use 'in' operator to search for <version> in undefined

[mikechabot]

What is the current behavior?
$ yarn command fails with the output below:

mchabot@XG01484 MINGW64 /c/_workspaces/xg-web (branching)
$ yarn
yarn install v0.16.1
info No lockfile found.
[1/4] Resolving packages...
error An unexpected error occured, please open a bug report with the information provided in "C:\\_workspaces\\xg-web\\yarn-error.log".
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.

Attached: yarn-error.zip
Attached: npm-resolver.zip

Error excerpt (yarn-error.log):

Trace: 
  TypeError: Cannot use 'in' operator to search for '^0.9.1' in undefined
      at C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\lib\resolvers\registries\npm-resolver.js:62:24
      at next (native)
      at step (C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\node_modules\babel-runtime\helpers\asyncToGenerator.js:17:30)
      at C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\node_modules\babel-runtime\helpers\asyncToGenerator.js:35:14
      at new Promise (C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\node_modules\core-js\library\modules\es6.promise.js:191:7)
      at C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\node_modules\babel-runtime\helpers\asyncToGenerator.js:14:12
      at Function.findVersionInRegistryResponse (C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\lib\resolvers\registries\npm-resolver.js:72:7)
      at C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\lib\resolvers\registries\npm-resolver.js:89:34
      at next (native)
      at step (C:\Users\mchabot\AppData\Roaming\npm\node_modules\yarn\node_modules\babel-runtime\helpers\asyncToGenerator.js:17:30)

What is the expected behavior?
$yarn install should create yarn.lock and install the project dependencies.

Please mention your node.js, yarn and operating system version.

• yarn@0.16.1
• NodeJs: v5.2.0
• Windows 7 (Service Pack 1)

[wyze]

This message indicates a malformed response from the registry. A friendly message has been added in #1356.