Check the ICA-500's ActiveX is installed on your computer

Go to C:\Windows\Downloaded Program Files and check to see if there is an entry for the file "WebWatch Class". The status column should show "Installed".
If the file is not listed, make sure your Security Settings in Internet Explorer are configured properly and then try reloading the ICA-500's home page. Most likely, the ICA-500 ActiveX control did not download and install correctly.
Check your Internet Explorer security settings and then close and restart Internet Explorer. Try to browse and log in again.