the applications files and folders under
/opt/bitnami/apps/civicrm/htdocs/ are configured with
daemon as the user and group owners respectively.
In order to modify or access to these files/folders, you should access using the
bitnami user. If you are using the launchpad console you are logged in using your default user, in order to use the
bitnami one, once logged you can run the following command
sudo su bitnami
With this user, you should be able to modify and access the files or folders. But, take into account if you created any file previously with the wrong user you should fix it changing the permissions, you can do it running
sudo chown bitnami:daemon PATH_TO_THE_FILE
Or if you are not sure about the changes and you want to modify it in a batch way, you can use
sudo chown -R bitnami:daemon /opt/bitnami/apps/civicrm/htdocs/
Please let us know if this solves the issue.
Carlos R. Hernández