can't upload themes or plug-ins

I’m new to WordPress. The past two weeks I’ve been developing a site and was almost finished with it when my links from the website to the localhost client just quit working. For about 15 hours I have tried to reestablish it. I finally decided to reinstall a new server and a fresh WordPress but now that won’t let me upload themes or plug-ins. wants the FTP name, userid, password. I’ve tried resetting in my system prefs and using these new settings but it then gives me an error saying wrong userid/password. I can dump the theme files into the admin-content theme directory but I’ve still lost so much and can’t upload zipped files with out the connection screen wanting the FTP info listed above.
So I go back to the original server and website that I designed the thing in and I still get the following… 404 error “The requested URL /wordpress/ was not found on this server.”
I’d really like to get the original server/website re-established because I was almost done with it all. Any help would be greatly appreciated.