The "NAME" that the error 215 is referring to is the server name at the other end. The "Name" in CFFTP is your query name.
At this point I would run FileZilla with full tracing/logging turned on, and see if anything funky happens when you connect to the ftp server. It will do a listdir automatically when it connects. Look to see if the server changes its name or something like that. The ftp support in CF10 is almost certainly different from that in CF8 or CF9, so maybe there is something that it is sensitive to.
Wishing this advice wasn't so vague, but at this point it looks like you need more information about the connection that what CF is going to give you. Keep us posted.
reed