Seriously the only thing I did different was not get the files off Mega because I had hit my limit yesterday while I downloaded them.
Okay, so you didn't get them off Mega.... But you don't say where you go them from. That is the important information. Not where you didn't get the files from... but from where you did get them from. Then we could have downloaded from that file host (or hosts) to see if there is a problem with those hosts.
For my experience:
I downloaded both Win64 v0.3.41.0 zip and the JAR from the GoFile links because - my god the other links were dreadfully slow (or, as in the case with Mega, it's over 2 Gigs and wanted me to download the Mega App, which I don't want to do).
Otherwise, I followed exactly what I said above:
And, as you can see from the video below, I had no problems.
So, either the file on the filehost you downloaded from has issues (rare) or your download had an error/didn't finish (more common) or there is something wrong on your end, over all (about as common).
I would recommend deleting and downloading from GoFile - all you need is the Win64 version because the weekly update has not been shared yet on here for this week.
Once the weekly update is uploaded - make sure to back up the JAR already in the game folder - download the updated JAR and move it to replace the one in the game folder. Once you are sure it is working, you can delete your back up.