We have a zimbra user who upgraded from OS X 10.5.4 to 10.5.5

Following the upgrade, CalDAV sync's fail.

This is from the Jetty log:
63.89.228.225 - - [17/Sep/2008:12:08:00 -0600] "PROPFIND /principals/users/jfred/ HTTP/1.1" 401 1420 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:12:08:00 -0600] "PROPFIND /principals/users/jfred/ HTTP/1.1" 207 1223 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:12:08:00 -0600] "PROPFIND /dav/jfred/ HTTP/1.1" 401 1408 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:12:08:00 -0600] "PROPFIND /dav/jfred/ HTTP/1.1" 207 22446 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:12:08:01 -0600] "PROPFIND /dav/jfred/Calendar/ HTTP/1.1" 207 602174 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:12:08:05 -0600] "REPORT /dav/jfred/Calendar/ HTTP/1.1" 500 1421 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:12:08:06 -0600] "PROPFIND /dav/jfred/Inbox/ HTTP/1.1" 207 9962 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:12:08:06 -0600] "REPORT /dav/jfred/Inbox/ HTTP/1.1" 207 80502 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:13:31 -0600] "PROPFIND /principals/users/jfred/ HTTP/1.1" 401 1420 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:13:32 -0600] "PROPFIND /principals/users/jfred/ HTTP/1.1" 207 1223 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:13:32 -0600] "PROPFIND /dav/jfred/ HTTP/1.1" 401 1408 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:13:32 -0600] "PROPFIND /dav/jfred/ HTTP/1.1" 207 22446 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:13:32 -0600] "PROPFIND /dav/jfred/Calendar/ HTTP/1.1" 207 602450 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:15:53 -0600] "PROPFIND /principals/users/jfred/ HTTP/1.1" 207 1223 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:15:53 -0600] "PROPFIND /dav/jfred/ HTTP/1.1" 207 22446 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:15:53 -0600] "PROPFIND /dav/jfred/Calendar/ HTTP/1.1" 207 602450 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:15:57 -0600] "REPORT /dav/jfred/Calendar/ HTTP/1.1" 500 1421 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:15:58 -0600] "PROPFIND /dav/jfred/Inbox/ HTTP/1.1" 207 9962 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"
63.89.228.225 - - [17/Sep/2008:13:15:59 -0600] "REPORT /dav/jfred/Inbox/ HTTP/1.1" 207 80502 "-" "DAVKit/3.0.4 (652); CalendarStore/3.0.5 (841); iCal/3.0.5 (1270); Mac OS X/10.5.5 (9F33)"

The Error Code 500's are what are being returned to him. We've not been able to determine the cause of this nor a solution. Any ideas would be welcome!

Rob