I have one of those cards in my laptop and it works well and easily.
The problem you are facing is that there are two methods of controlling a wireless card in Fedora. You are using the one called "Network Configuration". The preferred method of controlling wireless cards is "NetworkManager" which is a different program.
If NetworkManager is running, it automatically stops Network Configuration controlling your card and you get the error you have found.
If you have an entry for your card in Network Configuration where you are now on the "Devices" tab, highlight it and click "Edit". In the new window make sure that "Activate device when computer starts" is NOT ticked. If it is there then "Controlled by NetworkManager" should be ticked. That last will only be there if your Fedora is relatively up to date.
Then look for NetworkManager on the top Gnome Panel in the notification area to the right. When you left click on it, it should present you with available wireless networks. Left click on one to be asked for any encryption key and subsequently a password to hide it behind.
Should NetworkManager not be running, go to the Gnome System Menu - Adminsitration - Services, start it and NetworkManager Dispatcher and save the configuration.
That got mine going.
Post back if you have any problems.