I do think it's better to contact the author. Imagine someone would edit your work and publish it. Even though it is a fix. Edit: Recommendation: If you cannot contact the author, keep it private and start a "how to fix ..." thread so everybody can do it and have fun with the map. If the author awakes, he could adopt your changes easily and would be thankful, imo.
Thank you ManiFake for officially updating the map! Even though this map has some performance issues (I think those can be mitigated by turning off dynamic reflections) it is the only other hill climb map that I know of with a comparable track length to Pikes Peak and working AI paths. I especially like long hill climbs for pulling heavy loads with the T-Series or other trucks, especially underpowered ones ... it takes so beautifully long