Error – WordPress with Yahoo

I have tried installing wordpress on a yahoo website with enabled MySQL on the folder https://www.mcsun.org/MySQL . I tried installing wordpress on https://www.mcsun.org/Blog . Once I uploaded the files it gave me an error page saying “error in establishing database connection” I checked: the username and passwords are fine, but and so is the db name. I do not know if I am uploading the files to the right directory… ANY comments are appreciated! Thank you!!!