Cant copy the items. At least one item contains corrupt data

[edrean]

Whenever I want to copy/move certain messages in a user's mailbox I get the following error : "Can't copy the items. At least one item contains corrupt data." This happens on Outlook 2003 with Scalix Connect 11.4.5.9045 on Scalix Server 11.4.5.13150.

I found a thread with a similar problem here :
http://www.scalix.com/forums/viewtopic.php?f=3&t=12602

My case is a little different in that I cannot even copy/move the affected messages to different folders within the users mailbox, never mind not being able to copy/move it to a pst file. I have tried the option of editing the affected message before trying to copy/move it, but it doesn't work. I cannot try the recovery folder method mentioned, because we are running Community Edition. Nothing seems to show up with omshowlog when the error occurs. The error occurs on profiles with and without Smartcache enabled.

Is there anything else I can try? Why does this happen? What's going on here?
Please help!