On a computer that is running Microsoft Windows Vista, you cannot perform any editing tasks that you typically expect to perform. For example, you cannot perform the following tasks:
1) Compose a new e-mail message
2) Reply to an e-mail message
3) Create a new contact, task, note, journal entry, or appointment
4) Change any configuration in the Outlook Web Access options folder
Additionally, you may receive an error message when you try to perform these tasks.
On a computer on which you have installed update 912945, you must first click one time in the compose frame in Outlook Web Access before you edit text. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
912945 (http://support.microsoft.com/kb/912945/ ) Internet Explorer ActiveX update
On a computer on which you have installed security update 912812 that is described in security bulletin MS06-013, you must first click one time in the compose frame in Outlook Web Access to activate the edit control.
To resolve install the Microsoft patch 911829 on your Exchange servers. Click here for link to download page.