Has anyone here had conflicts using Outlook with Live Meeting in the mix?

We have a client using it and this is what they said:

We are having bad interactions between Microsoft Live Meeting and Outlook/Zimbra. Do you know of support issues with between Outlook/Zimbra and Live Meeting?

Appoints won’t transfer, Outlook crashes, can’t accept appointments

I don't have any knowledge of Live Meeting so this is tough for me to troubleshoot