Does it happen when you open all emails or just that one?
From what I've found (from limited results through Google), people seem to be having this problem and have apparently fixed it by disabling the "Speech and Handwriting" features of Office/Windows or installing
MDAC 2.8
Your error seems to relate to the "Smart Tags" functionality of Office though so I'd try disabling that.
Instructions
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You should also try and use
Office Update to ensure your copy of Office is up to date and you're not missing any patches which may have fixed this (even though I can't find any MS KB articles relating to it).
And alternatively, export your mail as a PST file and attempt to reinstall Office to see if that fixes it.
Chris
