Need help on three issues!

My website is aphyliebno.com and I have three issues. I'm trying to upload a new index.html but I get the following message: index.html - error occurred - An FTP error occurred - cannot put index.html. Internal data error, possibly because of failure to start the upload. Also, how can I correct these two coding issues: Special characters must be escaped: [<] (<area shape="rect" coords="812,24,1005,77" href="<a href="https://www.longandfoster.com/AphyLiebno" target="_blank">https://www.longandfoster.com/AphyLiebno</a>" target="_new" alt="Search for Homes">) and a mistake in here (<figure><iframe width="270" height="225" frameborder="0" scrolling="no" marginheight="0" marginwidth="0"