This will not be of much help but , last week I installed IIS on my laptop running XP Home, yes it can be done. Then I installed FM 8.5 Advanced and had the same problem, I tried everything and no admin console ever came up. Now after reading your post I went into the IIS mgr. Started IIS went to localhost/fmi/config and voila, the Admin Console appeared, first time. I have no idea what changed that caused it to magically appear. One major change on my machine was a ZoneLab upgrade, but I had shutdown Zonelab before, when it did not work. I wish I had an answer for you as I would like to know myself why it's now running. I'll keep poking around and see if I come up with anything.
Good Luck.