After the upgrade to SR4 Agent Email stopped working (Greyed oy login/logout buttons, Agent email Tab was blank). I trawled obvious sites for answers and failed. All the troubleshooting guides are out of date for this release as it installs Java 6. Rechecked the obvious UCCX to Exchange server settings. Finally after looking through Java Logs I found an error and some research led me to this Java setting
Open the Java Console,
Settings -> Java Plugin
Uncheck Enable the next generation Java Plug-in
This fixed my Agent E-mail issue.
I dont know if this is OS or browser specific, I'm using Vista SP1 with IE7
Hope this helps