I presume the SSID you have used successfully via your W98se desktop is 'BTVOYAGER2091-7D', so its the same broadcasted network you are trying to connect to with your laptop, and not next doors who also has a Voyager 2091?
The easiest way to check is the last 3 characters "-7D" which will be different for different installations.
Assuming the above, have you also set a range of IP addresses to be used within your network such as 192.168.1.1 to 192.168.1.100? or are you hard coding each rather then use the default NAT range?
Either ways, assuming you do not have any other devices trying to connect wireless to the same network, setting 192.168.1.2 as the next sequential IP address within your own LAN would be a logical suggestion.
In addition, if you have set MAC Addressing up (good idea), you will also need to add your Laptop's MAC address to the list for your network.
N/B I have no experience with your specific kit, but have read up on wireless networking before getting going with my own recently.