I just updated to 4.8.5.0, and still, I get 404 not found error. I must have something else set incorrectly. I'm now also allowing the PC to update Windows 10, which has not been allowed, either, for several months. Wish me luck on that!
Also, after the update of BI, it complained about my settings for clip storage and I had to choose a different folder for the database.
I've tried this with several browsers, and although everything works fine with UI3, I get 404 when trying to find "allcams.htm".
Edit to add:
The windows update didn't appear to have wrecked anything, and the new version of BI seems to run fine. I did have to let it rebuild the database after moving its location so it wouldn't complain, and everything seems to be working as before with no surprises noted so far.
I'm still unable to see the "allcams.htm" page, but it's not a big deal. I was just curious about using that after reading this thread.