Again, not knowing this box, I have a few more questions:
1). Does it allow more than one device to be connected at the same time?
2). Did you have to "add" the laptop, or it just added?
3). What error do you get? Timeout? Bad Password?
4). Make sure the WEP is set to
On the iPad, reboot it as well. Press and hold power, and shut it ALL THE WAY DOWN and restart it. See if that helps.
Lastly, try FORGETTING the network on the iPad. When it shows up, click the small right arrow, and on the next screen, say "forget this network". Then, when you select it again, it should ask for the password again. Type it slowly, as if you make a mistake, it sometimes just remembers this bad password and refuses to connect.
I have seen both my iPhone and iPod touch fail to connect exactly the same way, and rebooting the device and forgetting the connection helped.
Let me know if this helps.