By the way.. Here's some output captured by truss when running the vncserver script :
bind(3,{ sa_len = 2, sa_family = 0, sa_data = { } },16) ERR#49 'Can't assign requested address'
bind(3,{ sa_len = 2, sa_family = 0, sa_data = { } },16) ERR#49 'Can't assign requested address'
I'm not sure...