This has to do with java and Chrome not being fully compatible anymore.
Potential solutions:
#1 - If you are at school using a faculty machine you shouldn't be using the web version of Outlook to access your email. IMS has loaded the full version of Outlook on your machine. Click the start button and in the white search box start Outlook. You may need to configure/set it up the first time you use it.
#3 - If you are using chrome the address book is available and will work but not from within a new message or reply. Before opening a message click the address book icon in the upper right. Once you use it to find a person, right click on them and select new message.
