Ionic3 build Error - upgrading from ionic2 to ioni3

Yes I was able to fix that npm issue, now I tried building the project and faced the same issue again.

[WARN] Error occurred during command execution from a CLI plugin (@ionic/cli-plugin-cordova). Your plugins may be out of
       date.
[DEBUG] !!! ERROR ENCOUNTERED !!!
Error: Cannot set property 'fixed' of undefined in undefined at line undefined, col undefined, pos undefined
[DEBUG] Error: Cannot set property 'fixed' of undefined in undefined at line undefined, col undefined, pos undefined
        at BuildError.Error (native)
        at new BuildError
        (D:\app\node_modules\@ionic\app-scripts\dist\util\errors.js:16:28)
        at taskReject
        (D:\app\node_modules\@ionic\app-scripts\dist\worker-process.js:36:22)
        at
        D:\app\node_modules\@ionic\app-scripts\dist\worker-process.js:14:13
        at process._tickCallback (internal/process/next_tick.js:109:7)

Anything else which I need to do please let me know. I can start fresh if you want me to, with the current project in ionic2 to port to ionic3.

Thanks for your support.