The directory for the sub domain isn’t supposed to have them files in, it’s got to have the nitro-imager ‘dist’ folder contents inside not the nitro converted files, they are for the client.
1640281733
Make sure the imager server is running also.
Check you register page to see if the INSERT SQL for creating an account matches up with the table column contents for users, there could be something missing in the query or there could be a column in the users table without a default value
Nitro-imager uses .json files so if you're using flash only then it won't work unless you convert your gamedata files and just keep them in a folder for it to read, you wouldn't have to use nitro the files would just sit there for the imager.
About the habbo-imager you're currently using I...
Open up chromes console and check for errors, I’m guessing your using .swf files aswell so are you on a browser that supports flash? If not swfs won’t load.