Outlook 2003: No Accept Button on Meeting Requests

For the last week or so everytime I have had a meeting request it has come through with no "Accept" button, only the "Decline" and "Tentative" buttons.
I can accept them through my Blackberry, but I don't want to have to keep doing that.

Last Friday there was a company wide monthly patch that went out and this problem has only started since then. No one else in my office seems to be having this issue.

Please help!