You shouldn't have to identify a computer by name in Norton Firewall. This may be at the heart of the problem (same MAC and potentially same IP being used by two different computer names).
I would remove the named entry in 'specify computers' and put in an IP address or range instead.
Also, you mentioned using a crossover cable and then said DHCP is enabled! So what is issuing an IP to DONALD & DONALD-DEV and how?