It's trying to fire up ssh because your target has a single colon in it.
server:/path/to/stuff means "fire up ssh or rsh and make me a tunnel to
server"
server::module/path/to/stuff means "try to access an rsync daemon on
server and access path/to/stuff on module"
/path/to/stuff means "access /path/to/stuff on the local machine"
Hope that helps.
by Jim Salter