Solved! Wow. Thank goodness someone else was as dumb as I was and did the same thing and someone else was smart enough to figure it out. When I was first learning this, I stupidly transferred a theme into the wrong place and was supposed to delete the files, but it was late and I forgot in the morning. So those files were causing the problem. I had to delete over 300 but luckily I knew which one caused the problem and just had to match up file size with dates and folders and now everything is working. But without that error message above, I never would have found the solution. And I only found that from searching for Apache permalinks on Bluehost. Needle in a haystack!