Yes, I know, this is why I also included a working link in my post.

Hi everyone. Thanks for the interest to new engine. I mainly wanted to say that the link in the top post is outdated; I edited the link in the post on 1-bit music forum, but the post here was not edited accordingly.

The latest version of the engine is here: http://introspec.retroscene.org/beeper/octode_xl_v1.zip

The .xm file supplied with the original distribution was not good. The new version has a proper .xm (hopefully).
I'll do my best to keep you informed if/when the engine will be further updated.