I downloaded your index.php file and all of the line breaks were removed. The entire file was on line 1.
I added line breaks back including changing things like: <?phpif
I now get the same error on another file. I'm thinking this might be an issue in a lot of files on your site.
That is what was causing the issue. I'm not sure what removed all of the line breaks. What are you using to upload the files? The issue was the corrupted index file.
My only guess is that the FTP program you are using is removing the line breaks.