ok, I tried. I reinstalled the newest driver (which was already installed, dated 15.06.2022)
-> did not work
BUT
I thought, 15.06 is quite new, so maybe thats the reason
so i installed an older version (GeForce Game Ready-Treiber WHQL 472.12 September 20, 2021), and
NOW IT WORKS AGAIN

so thank you for guiding me to the right path, and for information if anyone else has the same problem with the newest nvidia driver

ok, I tried. I reinstalled the newest driver (which was already installed, dated 15.06.2022)
-> did not work
BUT
I thought, 15.06 is quite new, so maybe thats the reason
so i installed an older version (GeForce Game Ready-Treiber WHQL 472.12 September 20, 2021), and
NOW IT WORKS AGAIN

so thank you for guiding me to the right path, and for information if anyone else has the same problem with the newest nvidia driver

since yesterday i get the same message as the OP, and have no idea why.
things I tried since that:
-all kind of selections when you right click the supremecommander.exe (combability mode, start in 640x480,... everything possible)
-deleting and reinstalling supcom
-installing directX from the supcom folder
-of course several restarts
-starting the game from steam directly (same message), the last several tries after restarting the PC were always just directly from steam

anyone has an idea whats causing this? before this weekend i was able to play without problems, since yesterday no chance