Otto...trust me, I have been through every step along the way, every post, every link, every .htaccess modification, and nothing has worked so far (for me anyhow) besides disabling the WordPress Stats and Cache scripts. There are some specific errors posted here that are not mentioned in your like or the other spinoff links. Lots of the errors in this thread are not being fixed by the link that you hate to keep pointing out. I am sure it has solved the issues for some folks, but it's not the magic fix for the rest of us.
One constant I can prove, is that small files (< 200k) will upload 100% of the time, while anything (> 300k) is a failure. I don't pretend to understand it, but I have gone through every resource available here so far and nothing has worked.
I can, and am able to work around the issue, so all is not lost, it's more of a convenience and the ability to run things the way I was prior to this error showing up. I appreciate the help that is being give here, it's just not working in all of these cases.