is this a stand-alone AP?
1) if it is stand-alone then you need to give more detailed error message.
It may be your browser security setting prevent the applets loaded from the AP to run.
2) if not (your environment is controller based) than you first need to enable the web access to the AP from the controller first!
3) the AP image is controller based, but you do not have a controller, then you need to load stand-alone image on the AP.
connect a serial console to the AP and inspect the output
