Found solution for Bitnami Report server 404 error
1) If the user has already installed tomcat and has entry in the path as Catalina home, first you remove that entry from the path and environment variable.
2) Rename your existing tomcat folder temporarily (That you might have installed in the past, do not rename C:\Bitnami\reportserver-3.0.2-7\apache-tomcat)
3) Uninstall Bitnami report server and delete all files under /Bitnami folder
4) Restart your laptop / desktop / Windows OS
5) Re install Bitnami report server
6) this time while installing the report server software will not find any apache tomcat on your local in other words it will refer to the tomcat "C:\Bitnami\reportserver-3.0.2-7\apache-tomcat" folder.
7) After successful installation, you will be able to run Bitnami report server : http://127.0.0.1/reportserver/
I have a suggestion to Bitnami Report server software - When you already are providing apache tomcat, why do you rely on tomcat server that is already installed?
Please do not check path entries of tomcat and rely on your own tomcat version 9 that comes with the application.