What is the version of your IE/Firefox?
"The Cisco WCS user interface requires Internet Explorer 6.0/SP1, Internet Explorer 7.0 with the Flash plugin, or Mozilla Firefox 2.0.2.11 or later. The Cisco WCS user interface has been tested and verified with Internet Explorer and Firefox on a Windows platform.
Using a web browser running on Windows 2003 to access the WCS web GUI is not recommended because recommended Windows 2003 security settings may cause browsing problems.
The client running the browser must have a minimum of 1 GB of RAM and a 2-GHz processor. The client device should not be running any CPU or memory-intensive applications."
http://www.cisco.com/en/US/docs/wireless/wcs/release/notes/WCS_RN5_2MR05.html#wp68364
Hope this helps. Please rate when applicable/helpful.