I apologize for not checking back here sooner. -_-
What I did was I uploaded the index.php file of WP1.5 (the short and sweet one) and just changed the directory of wp-blog-header.php from ./wp-blog-header.php to domain/blog/wp-blog-header.php. The reason (I think) why I was getting errors was because I had pointed the specific URL of the file (so instead of just domain/blog/, I put in https://www.turbo-geek.org/domain/blog/ instead). I have no idea why this messed up my index file, but it did, and changing what I had put in earlier for the URL of the file worked out for me somehow.
Once again, I apologize for not doing what was expected of me. Sorry.