I have a Yahoo! Domain name and it came with a program called Yahoo! sitebuilder, a nice program for a simple site but not enough features

. So I was looking for an alternative and came up with Dreamweaver, I really got used to that until it came to putting it on the web. For the site I used photoshop to create the whole backround and then I added UNDER CONSTRUCTION to it using macromedia dreamweaver. I tried to use FlashFXP to upload it to the web and I deleted everything off of it first (all folders; all Yahoo! sitebuilder stuff) and I just put my newly designed website (index.htm) I saved onto the website through FTP (not in a folder, just in the main directory). When I went to look at my site it lacked the background, it just had the under construction thing. So how do I upload my site to my Yahoo! Domain.
PS I also tried using Dreamweavers "save to remote server..." and that always comes up with a FTP error or no permission thing.