I have checked that this file does not exist. All the discourse files are under
/opt/bitnami/apps/discourse/htdocs. Note that the post was written in 2014, so probably it has changed.
This is our general guide to install a plugin:
However, if you continue facing issues installing LDAP plugin, we suggest you post your question on the official support forums of the application or on the plugin repo so others can help you with your issue.
Do not hesitate to ask us any questions you have