I'm still getting "Database Error" when I want to view "Sent Items".
In the message list I can see that I have replied to messages (marked with a backward arrow) , but in the "Conversation" view all my sent messages are not displayed.
I've just found out that in my message settings "Save a copy of each personal message in my sent items by default." was disabled.
It looks to me that this could be the reason, but enabling it didn't change anything for still getting the above mentioned "Database Error".
Maybe I need to send again a message to have a look whats happen.
Just a thought: could it have something to do with that my profile username differs from my display name?
Thank You already.