Maybe try chmod 777 on /wp-content/uploads/ and check the “Recurse into subdirectories” in the Filezilla dialog.
Did all the WordPress files finish uploading to the new Linux server?
IE may have a separate CSS file for the login page. I’m thinking maybe those files didn’t upload, and those files would style the logo for the login page.
Not sure, just a guess.
Chmod the /wp-content/ directory to 777?
You can do this using an FTP program, like FileZilla.
