Originally Posted by
Ares_Casai
So ... I seem to have solved the problem. I tried installing everything on two other machines and creating a mod on them, on the theory that maybe it was a weird hardware or OS bug with my gaming rig. When I was trying it on the second machine, I messed up on step #23. Instead of clicking cancel on the error, I clicked OK by mistake, and BOB finished everything successfully. I went back and tried the same thing on my gaming rig, and it worked there too. I put the mod.pack file in my data folder, and it worked--my changes showed up when I started a campaign.
Apparently, step #23 should be: wait for the error message on Steam, and click OK.