The first is a recently upgraded version, whilst the second was a brand new install. When I had first installed them, they worked flawlessly. However, just the other day, I revisited the first (my main blog) and it gave me the current error, or:
"It doesn't look like you've installed WP yet. Try running install.php."
I... have no idea why it would say that. It may be that I'm just an idiot, but regardless, it makes no sense that it would work one minute, but not the next. Such is the way of the Internet. Any suggestions?