webmail question with sent-mail folder

[Michael Doerner]

For an E-smith demonstration for a client, I was playing a bit more with
webmail and came across something strange:

When I finally send a new message it comes to the following screen:

Message sent successfully, ERROR: not saved to sent-mail.

And webmail is doing exactly this. The message is sent but no copy is stored
in the sent-mail folder.
Am I doing something wrong?

Thanks for any hint,
Michael Doerner