Ok, let's check to see what the directory is for your domain then.
On your DreamHost Web Panel in the left column, click on "Domains" then click on "Manage Domains".
You should see a list with columns for Domain, Registration, Web Hosting, Security, Email, and Actions.
Under Web Hosting, you should see something like this for your domain: (If not, you may need to setup your account for web hosting. I suggest Live Chat for more answers on that.)
Fully Hosted with PHP 5.6 (User: YOURUSER)
Edit | Remove
Click on "Edit" and you will see a section titled "Users, Files, and Paths". We are interested in the "Web directory:" path. Should be something like /home/username/ and then a textbox. The contents of the textbox is the folder that your files should be uploaded to via Filezilla.