The MeetingBooster Plug-in works best when you are using Cached Exchange Mode in Outlook.
Cached exchange mode is usually on by default, but if it is not on you can switch it back on by doing the following:
Step 1: Open Outlook and go to File -> Account Settings.
Step 2: Select your account and click “Change”.
Step 3: Check the option to “Use Cached Exchange Mode”
Step 4: Click “Next” and “Close”. The first time Outlook starts it will cache your emails, and calendar, and this can take a few minutes depending on how much you have in your account. The status line in outlook will say “All folders are up to date” when done