powerbook g4 wieless issue

I have recently been given a powerbook g4 with tiger 10.4 preloaded, I have connected wirelessly to this, via my sky broadband wireless connection, but last week, i gave the powerbook to my brother to use, and he has been having great difficulty connecting to the wireless network at his house, using the BTHome Hub, when connecting the powerbook picks up the connection, and asks for the network key, on entering this the message displayed is error in connection, as though it does not recognise the key, or either the hub, strange