I think I bit off more than I can chew.
We've got an old oscommerce site at http://www.libreria.it, which we thought needed updating. Someone suggested that we try installing WP on a sub-directory to see if we like it, so we did. It's at /wordpress.
We love it, but the e-commerce plugin configurations are conflicting with our existing oscommerce settings. So someone suggested that if we own another domain (which we do), we could move it there and try out everything with modified php settings.
I followed the steps here:
I got to step 9 - moving the files to the new domain in my FTP client (Transmit), and I got the error:
Could not move “index.php”. Server said: Rename/move failure: Invalid cross-device link
Error -150: could not rename remote file
Now I can't access the admin panel, I can't move the files, and I have NO IDEA what I'm doing.