You are using AP and not wireless routers on the other floors?
When you are on the floors you can't connect, DO you see the AP?
Using Zero Config.
Delete the SSID network that is not working.
Select View Wireless Networks?
Does it show UP?
Select, enter WPA-TKIP key
Check the advanced option, make sure it is set fot AP or Infrastructure.
Some AP (my usr) has the capabilities of mac filtering and Access control. May want to check yours.