I got it and fixed it.
I just installed the generator (locally and not globally)
C:\PhoneGap\Workspace\Demos\cordovayeoman>npm install generator-angular-cordova
after the successful installation of the package. When I ran: "yo angular-cordova" I got the same exception (see snapshot)
then I created another folder (MyCordovaApp) inside "the folder" where I installed/configured the generator plugin i.e.
From: C:\PhoneGap\Workspace\Demos\cordovayeoman\
To: C:\PhoneGap\Workspace\Demos\cordovayeoman\MyCordovaApp
Now here I ran again: "yo angular-cordova" and it worked well :) (see snapshot)
Note:- I had selected iOS platform that's why it given me excetion while generating stuff for iOS on Windows machine.
and here is the generated stuff.