In general, a little strange, is this a coincidence? The name of the file you want is 2021, just like it's 2021, but oh well. With older games like this, we used to install RTP packages that allowed these games to run without having the RPG maker itself. In my case, I have both the program itself and the installed package. In even more prehistoric times, some simply pasted the file into the game folder from that package, but it had the name 103 if I'm not mistaken, and then everything worked. But for some reason your game requires 2021, so here I can only advise the following:
Either search the Internet for RPG Maker RTP packages for the VX version (not to be confused with the VX Ace version), or search the Internet for the program itself and download it. It will install all the necessary files, and if EVEN AFTER THIS the game will not start, then I do not know what to advise.
Although you can try to simply download the game from this site, and maybe all your problems will be solved, it is at least worth trying, this is the fastest and easiest way. Good luck!
P.S.> I also remembered, try right-clicking on the game icon and open the properties. In Properties, find the Attributes: Read Only section. Uncheck the Read-only section, click Apply, and try running the game, it might help. Oh, and also on the way to launch the game, it is desirable that everything be in English, for example D / games / etc.
To explain all this, I used a google translator, I apologize if it came out clumsily, but as best I could.