I may be way off base here, but I have found when referencing parts of the app by path - especially files outside the CakePHP but on the same server (not the case here) - is that the folder you run the cake server from is relevant. Running the cake.php from a folder higher than it (like how the tutorials on WAMP say to do, ie. cd app then bin\cake server) will break it.
So just to remove that as a possibility of not losing paths relative to root, run the server from the same depth. Personally I run it from webroot as that feels right to me cd app\webroot then ..\bin\cake server - but as the paths are relative there’s no reason you can’t just cd app\bin then cake server.
This may not help you now, but it could bypass errors you may yet encounter.