SUCCESS!!!! (on installation anyway)
(for anyone who skipped over my previous posts, I downloaded the game from Capcom on my main pc, hit cancel when it wanted to install there and copied the installation folder over to my arcade setup)
I installed the games for windows live, direct x, .net 3.5 (even though I had 4.0 installed) and whatever else was in the support folder.
Then tried to reinstall the game from the setup menu and kept getting the same error message (looked up the code and it was a generic untrusted certificate something or other)
Then I installed it from the installer package like I did the first time, expecting the same result.
This time it worked though and the game loads completely and plays.
Not sure I should mention this, but it never even asked for a product key or activation code?!?

I was all psyched up to recommend the game at that point, but the controls are all screwy. After mapping the controls, you still need to use the ENTER and ESC keys to select stuff. No other button works for it. I doubt autohotkey would help because the script that makes my middle mouse button register as ESC doesn't work. Player 2 start doesn't work, so I have no idea if the other controls work. Maybe offline mode doesn't support 2 players?

Odd thing is that when I press P2 start while in a match, the P1 pause menu comes up. I remapped the controls twice and that still happens. After restarting the computer and launching the game, it returned to the default mappings. Maybe I'm just doing something wrong. I'll research the issue at work tomorrow.
Also, not all characters are available offline, but Capcom themselves are supposed to release a patch sometime soon to address it.
http://www.capcom-unity.com/sven/blog/2011/06/02/ssfiv:_ae_pc_%E2%80%93_drm:_we_had_it_wrongHere are the ones currently available offline:

As an aside, I launched the cracked taito x arcade version of SFIV and was amazed how fast it loaded and how perfectly everything worked.

If the 2 player version is ever leaked, that's the one to have on a cab, less characters or not.
EDIT:Gave up and applied the keyboard patch from the old SFIV folder. Didn't even have to configure anything. Just copied the files over and it worked perfectly.
I'll still have buyer's remorse until they release the patch to make all the characters playable. As it stands now, there was absolutely no reason for me to buy this game, as the old one has more playble characters. On the upside, gameplay does seem noticeably faster.