You're also stuck on the exact same problem as @KAILAS, using the exact same versions of Chef? Are you on the same team?
I expect part of the error is that at a point in time (when we originally built that version) the versions of Chef, Omnibus, Omnibus-Toolchain, Ruby, RubyDevkit and all the dependencies worked together on the latest stable version of all of them. So to recreate a full build of Chef 12.21.3 you would need to go back in time and figure out what all those dependencies were at that point.
I'm still a little confused/perplexed at why there's a need to build/package Chef 12.21.3 for Windows though. This is a pretty unsupportable configuration. I'd like to understand your needs more though. Please can one of you email me with the requested info?