In a away a mixed bag of news good from the stand point that the firewall program helps to keep out unwanted visitors out but bad because it hurt's you in the end as it's is the cause of your wii issue. It is a double edged sword one hand it protects your internet enable devices and on the other hand it blocks the wii which you want to connected the internet from doing it's own thing. If you could disable the spi firewall then you are open to any attack coming your way with it your some what safe but the wii game internet connection is blocked which is more important network safety or playing a game on line?
