Hi Susan,
I hope to help you get this sorted.
Are you using an FTP client? If so, which one?
Are you sure you're uploading to your main "www" public web folder, or a subfolder (recommended) such as www/mail? (Unfortunately I can't remember the actual "www" folder name on DreamHost.)
What error messages are you getting?
When you connect via FTP, what folders do you see, where do you browse and where are you attempting to upload ListMail?
Regards