First of all, please note that it's completely secure to use the 80 port in this case. As you are creating a SSH tunnel, all the communication is already secure so you don't need to worry about that.
Regarding the error you obtain, what is it? Please note that you will need to use https://localhost:8888 (note the s in https) when accessing the application. Apart from that, you will probably receive a security warning about the certificate. That's normal because you are accessing the app using localhost instead of your domain.