First, the port is 21. The default value is stupid, I know that and I keep forgetting to change it on new releases.
Second: your directory is wrong. You have to enter the FTP directory, not the file system directory. In order to figure out the correct setting, do this. Connect to your site with FileZilla and navigate to the backup output directory. When you're there, take a look at the right-hand pane, above the folder tree. You can see a path like /public_html/administrator/components/com_akeeba/backup. Copy it and paste it in Remote Control's "FTP Path to backup output directory". Click OK, retry, it'll work now :)
FYI, this is documented in
the site definition editor's documentation page, accessible by clicking the Help (cross) icon on the bottom right of the dialog itself. Just look for the "FTP Path to backup output directory" heading.
Nicholas K. Dionysopoulos
Lead Developer and Director
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