What are you trying to upload – RH project files or the help output you’ve generated? It’s not clear. If it’s WebHelp, your starting page can be called anything you want by setting it in the SSL recipe.
Trying to upload help output that somebody else generated.. WebHelp.. When I'm uploading the index page, i'm getting an upload error. When I rename the page to, say, abc.html, it uploads, but renders blank..
Sounds like something in your web server environment isn’t liking index.htm – you can set the start page name in RH in the SSL recipe before generating the help to whatever you want and it will reflect throughout the project so that your links will work.