Got the same problems like you...
Try to use the Abandon Loader and set "Windows95-Compatibility" for WC3KS (and DON'T set VDMS).
https://www.wcnews.com/news/update/5058
With this programm i could play the first mission. But after the landing video with Rachel the game freezes again. Maybe...
Just for the record: i solved my "Files=25"-problem. I had to set this line in the config.nt of Windows. Now my old WC3 works with small sound-problems. It's not perfect, but it's playable. :)