You hvae to disconnect wclClient before connecting with wclOPPClient. Phone remains in OBEX mode. Nokia uses its own protocols for USB/Serial and it is impossible to send files to it with AT commands. For some SonyEricsson and Nokias, connected over USB, you may use wclOPPClient directly without switching phone to OBEX. There will be something like "OBEX USB" in your Device Manager and you may use it. At least, it works for SE K750i and for N95 8gb.