You're probably missing a step or have something wrong. The last time I got this error was because I had the wrong connection string. I'd suggest you check that first. Don't just look at it, tho. Ensure the user/password combination works when you manually login to SQL Server and also test the exact connection string from another application. This will ensure it's valid.
As far as creating a video, we look forward to you providing one to us
Like I said before, suggestions or appreciated, but actions speak louder than words. We're a volunteer force and people use DNN because of its feature set, so of course this is where we focus our efforts. If someone would like to submit documentation, we'd be happy to validate/post it. Again, I'm not saying that there aren't problems with the documentation or even the application. I'm simply saying that without help in resolving these issues, it's hard to get the docs updated. People expect bug fixes and enhancements, but docs are just a nice to have when you're getting setup. Once you're setup, nobody cares about docs.
Again, the reason for a combined install doc is for our benefit in managing them. Nobody likes to update docs, especially not two sets of docs that are 90% identical, if not more.
If you think Apache/PHP are better than DNN, you're in a league of your own. That's just my opinion, tho. Apache has got to be one of the hardest to configure applications I've ever managed. Luckily, like DNN, once it's setup, you don't have to worry about it.
I've provided a few suggestions, but sometimes it takes a good deal of initiative to track down problems and get them fixed. If you find out exactly where you went wrong, let us know and we can attempt to better the docs for that. Without this explanation, we can't change anything, and the docs stay as they are - with or without falacies. Like I said, more often than not, install/upgrade problems are because of missed or misinterpreted steps. Of course the docs can be better, but we need your input and corrections in order to do this.