Does this happen with all logs, or just with some specific ones from certain contacts only?
Does it only happen for contacts for which you have a conversation going on at that very same moment? If this is the case it might be that those logs are locked. In that case close the conversations first.
Other than that I can't help you, sorry.
If nobody has a solution for this you might want to try to contact the support team of Windows Live Messenger:
https://support.live.com/default.aspx?productkey=wlmessenger
Make sure you give more than enough details though; you need to help them helping you.
But, you might want to abscure the emails in your screenshot by editing the screenshot with a graphics program. I'm not certain if your contacts would appreciate it if you show their email addresses like that.
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