Firefox4 on OSX 10.5 (leopard) failing to open from command line : bang_head_on_wall

I needed to launch Firefox from the command line in OS X 10.5.8, and it just wouldn't work. This blog post saved me:

Firefox4 on OSX 10.5 (leopard) failing to open from command line : bang_head_on_wall

So very easy to fix!