Well in fact I still have a problem with CalDav synchro on my Mac Pro

I have setup manually my CalDAV account in Ical, then it retrieves calendar from server and displays events in iCal but it still displays an Exclamation sign near the account and I have some events in CalDAV queue of Ical !!
I include a scree capture of it !
If I remove the account and let the iSync Zimbra plugin creates it it does exactly the same

So what's wrong ?
Thanks in advance for help
Vincèn