[Synckolab] Problem synchronising calendar with [0.4.18]

[Sebastian Held]

Hi,

Using the following software versions:
SyncKolab 0.4.18
Thunderbird 1.0.6
Kolab 2
I've a problem to sync the calendar elements generated by thunderbird to the 
imap folder.
There is no problem the other way round. Events generated by Horde or Kontact 
are displayed in Inbox/Calendar and synchronised to the calendar component.

There is one object in Inbox/Calendar: libkcal-1804833025.578
I created another one in thunderbird/calendar, but this does not appear in 
Inbox/Calendar.
JavaScript Console:
----
got folder: 'imap://sebastian@rom.test/INBOX'
Calendar: got folder: imap://sebastian@rom.test/INBOX/Calendar
Message Folder: imap-message://sebastian@rom.test/INBOX/Calendar
parsing message...
server changed: libkcal-1804833025.578
DONE
starting update content...
we got this card: libkcal-1804833025.578
New Card
----

It seems to me, that SyncKolab is not able to write to the imap folder...
How to debug this? (Venkman is installed)
Any suggestions?

Thanks,
Sebastian Held