I'd probably just document the fact that Outlook is broken and not supported, or do what jZed suggests. You may be able to do a better job if you parse the problem lines yourself and examine individual fields for clues on where you are at in a "line".
in reply to Regex with malformed CSV files
For example, most fields will probably not have embedded newlines in them; a zip code will probably not have embedded quotes or commas and will probably be short; email addresses will tend to have '@' in them; quoted fields will probably not strech 100's of characters; etc.
If you enforce some rules like this, your parser may be able to determine most of the time where it is. Of course, you could go stark raving mad in a futile effort trying to figure out the perfect ruleset...