Error while executing r.js optimizer, what could be the possible issue

Question

While executing require.js optimizer for bundling my backbone application, I am getting this error

Tracing dependencies for: ./require-config TypeError: Cannot read property "normalize" from undefined In module tree: requireLib

Here is the code of my build.js

({
    baseUrl: './',
    mainConfigFile: './require-config.js',
    name: './require-config',
    out: './scripts.min.js',
    preserveLicenseComments: false,
    paths: {
        requireLib: './lib/require'
    },
    include: 'requireLib'
})