The error message notifying that some files were not found means that the plugin lacks permissions to move the templates required for its work from the plugin folder to the theme folder. To have the plugin running correctly, please follow the instructions in the message:
1) Open /wp-content/plugins/realty-pro/templates/ directory;
2) Copy the files from this folder ("rltpr-agent.php", "rltpr-listing.php", "rltpr-nothing-found.php", "rltpr-search-agent-results.php", "rltpr-search-form.php", "rltpr-search-listing-results.php", "rltpr-sidebar-listing.php");
3) Open the folder with your theme and add the files you just copied.