Thanks for the tip tgl1992. But I saw that post before posting here. I typically run the game with admin privileges, so that particular workaround didn't do anything for me.
But I somehow got this resolved shortly before seeing your post here. Right after loading steam and getting that error for the first time, I noticed one of my keyboard LEDs was constantly remaining on. It remained on after removing steam from the task manager.
So I restarted my system and reloaded steam. The keyboard leds went off as they typically do and the game launched normally.
I think this may have something to do with a server issue on steam end. But regardless, it appears to be running ok now.
regarding the beta patch: are you using this without any issues? I'm nervous about participating in this because it could f@ck up my mod setup. I'm also worried it may take the devs longer to produce an official patch as they're no longer working on the game