I haven't looked at your quasiquote examples in particular, but note that standard Arc uses MzScheme's quasiquote expander, which is buggy for nested quasiquote expansions.
Fortunately it's easy to use a working quasiquote expander: it's a one line change to the Arc compiler so that if a "quasiquote" macro has been defined, it gets used instead of the builtin MzScheme version. Then we can load a quasiquote implementation written in Arc, such as fallintothis' port of the Common Lisp quasiquote expander.
