Node.js 0.8.0 x64 on Windows won't install Grunt

Trying to install Grunt with npm install -g grunt (node.js version 0.8.0) will produce an ETIMEDOUT error. An HTTP proxy is configured in .npmrc using http:\\<servername.com>:<port> format.

However, the same install command, with the same settings on the same machine, with node.js 0.6.19 installed would successfully install Grunt.

Any help is appreciated!