Hello juriss,
I’m not familiar with the old manual way to install translations. The current way is as follows:
1. Go to Settings => General, and set Site Language to your language. The admin language switches immediately to your language.
2. Go to Dashboard => Updates (now in your language) and, at the bottom of that page, click Update Translations. All the available translations for your themes and plugins are automatically installed, and their language switches to your language.
3. Translations for BP Distance Search are not available yet, but you can add one yourself on https://translate.www.ads-software.com/projects/wp-plugins/bp-distance-search/. When you complete the translation, it will become available as explained in step 2.
Please let me know if this works for you!