phonegap build android - An error occurred while building the android project

When building my Phonegap Android project I got this error during compile:

[error] An error occurred while building the android project. 

/Users/edpitt/Projects/MyProj/platforms/android/cordova/lib/check_reqs.js:35

        return target.split('=')[1].replace('\n', '').replace('\r', '').replac

                                    ^

TypeError: Cannot call method 'replace' of undefined

    at Object.module.exports.get_target (/Users/edpitt/Projects/MyProj/platforms/android/cordova/lib/check_reqs.js:35:37)

The only way I could work out a fix for this was by switching workspace in Eclipse, and then importing the code into that new workspace.