Read the manual, page 8.
If that fails continue like so:
https://www.subsim.com/radioroom/sho...63&postcount=4
You need a clean install, check above post to see how to do that. Then install LSH3 as per the manual. Make sure you use the newest version, that your download is not corrupted and that you (initially) don't mix in other mods. Activate the included mods one by one.
If that fails be prepared to describe step by step what you did and to produce a mod list.