Can you attach the vCalendar of the event (it should contain the vTimezone and the vEvent)?

Here is what I found:

If I backup the calendar with sogo-tool, remove the calendar and try to restore it, the restore chokes (dumps as well) on some events:

"
2013-02-06 19:25:31.705 sogo-tool[12952] restoring record '00000000A04B7D0493165C4D9FBCC00594B3C989A49A2B00'
sogo-tool: Uncaught exception NSInvalidArgumentException, reason: iCalRecurrenceRule(instance) does not recognize orderOfValueKeys
Aborted (core dumped)
"

Here is the event's vCalendar entry:

"
{
"c_content" = "BEGIN:VCALENDAR
VERSION:2.0
BEGIN:VTIMEZONE
TZID:Europe/Istanbul
BEGIN:DAYLIGHT
DTSTART:20120325T030000
RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3
TZOFFSETFROM:+0200
TZOFFSETTO:+0300
TZNAME:Europe/Istanbul
END:DAYLIGHT
BEGIN:STANDARD
DTSTART:20121028T040000
RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:+0300
TZOFFSETTO:+0200
TZNAME:Europe/Istanbul
END:STANDARD
END:VTIMEZONE
BEGIN:VTIMEZONE
TZID:GMT
BEGIN:STANDARD
DTSTART:19700101T000000
RDATE:19700101T000000
TZOFFSETFROM:+0000
TZOFFSETTO:+0000
TZNAME:GMT
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
UID:00000000A04B7D0493165C4D9FBCC00594B3C989A49A2B00
SUMMARY:Marjatta
DESCRIPTION:
LOCATION:
CATEGORIES:Birthday
CLASS:PRIVATE
DTSTART;VALUE=DATE:20120420
DTEND;VALUE=DATE:20120421
PRIORITY:5
STATUS:0
RRULE;VALUE=DATE:FREQ=YEARLY;INTERVAL=1;BYMONTH=4;BYMONTHDAY=20;UNTIL=20300419
X-FUNAMBOL-FOLDER:DEFAULT_FOLDER
X-FUNAMBOL-ALLDAY:1
X-FUNAMBOL-FOLDER:DEFAULT_FOLDER
X-MICROSOFT-CDO-BUSYSTATUS:0
X-MICROSOFT-CDO-REPLYTIME:
X-FUNAMBOL-BILLINGINFO:
X-FUNAMBOL-COMPANIES:
X-FUNAMBOL-MILEAGE:
X-FUNAMBOL-NOAGING:0
END:VEVENT
END:VCALENDAR
";
"c_name" = 00000000A04B7D0493165C4D9FBCC00594B3C989A49A2B00;
},
"

Here is another from other user's calendar:

                "c_content" = "BEGIN:VCALENDAR                              

BEGIN:VEVENT
UID:19C8-4F87FC00-21-45C8D680
LAST-MODIFIED:20070605T123101Z
SUMMARY:Kes\U00E4loma
DESCRIPTION:Kes\U00E4loma
CLASS:PUBLIC
STATUS:CONFIRMED
ATTENDEE;CN=John Doe;ROLE=CHAIR;PARTSTAT=ACCEPTED:MAILTO:john.doe@domainremoved.fi
DTSTART;VALUE=DATE:20070716
DTSTAMP:20120413T095852Z
DTEND;VALUE=DATE:20070716
RRULE:UNTIL=20070721T000000Z;FREQ=DAILY
END:VEVENT
END:VCALENDAR";
"c_name" = "19C8-4F87FC00-21-45C8D680";
},

If I delete the events from the backup file and then restore with sogo-tool, the calendar starts working. But some of the users have quite many of these kind of events so fixing them manually isn't really a good option...

Can you identify what the problem is from these events or should I produce more examples?

Going through the calendar entries I found broken ones that were generated via SOGo as well (I think the ones I reported earlier were originally from other sources like Funambol). Here is an example:

    {
        "c_content" = "BEGIN:VCALENDAR

VERSION:2.0
PRODID:-//Inverse inc./SOGo 1.3.12//EN
BEGIN:VEVENT
UID:3692-4FA3A180-359-2DB5B280
SUMMARY:Oma meno
DESCRIPTION:Bohemia / KO
CREATED:20120504T093050Z
DTSTAMP:20120504T093050Z
LAST-MODIFIED:20120507T055506Z
DTSTART;TZID=Europe/Helsinki:20120515T140000
DTEND;TZID=Europe/Helsinki:20120515T160000
TRANSP:OPAQUE
END:VEVENT
BEGIN:VTIMEZONE
TZID:Europe/Helsinki
X-LIC-LOCATION:Europe/Helsinki
BEGIN:DAYLIGHT
TZOFFSETFROM:+0200
TZOFFSETTO:+0300
TZNAME:EEST
DTSTART:19700329T030000
RRULE:BYDAY=-1SU;FREQ=YEARLY;BYMONTH=3
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0300
TZOFFSETTO:+0200
TZNAME:EET
DTSTART:19701025T040000
RRULE:BYDAY=-1SU;FREQ=YEARLY;BYMONTH=10
END:STANDARD
END:VTIMEZONE
END:VCALENDAR";
"c_name" = "3692-4FA3A180-359-2DB5B280.ics";
},

Have you updated all the SOPE packages?

These are the packages I have installed:

gnustep-base-1.23.0-1.i686
gnustep-make-2.6.1-1.i686
lasso-2.3.6-1.centos6.i686
libffi-3.0.10-1.i686
libmemcached-0.49-1.i686
python-lxml-2.3.3-1.centos6.i686
sogo-2.0.4b-1.centos6.i686
sogo-ealarms-notify-2.0.4b-1.centos6.i686
sogo-tool-2.0.4b-1.centos6.i686
sope49-appserver-4.9-20130204_1664.el6.1.i686
sope49-core-4.9-20130204_1664.el6.1.i686
sope49-gdl1-mysql-4.9-20130204_1664.el6.1.i686
sope49-xml-4.9-20130204_1664.el6.1.i686
sope49-ldap-4.9-20130204_1664.el6.1.i686
sope49-cards-2.0_20120418-1.centos6.i686
sope49-gdl1-contentstore-2.0.4b-1.centos6.i686
sope49-sbjson-2.3.1-20130204_1664.el6.1.i686
sope49-gdl1-4.9-20130204_1664.el6.1.i686
sope49-gdl1-postgresql-4.9-20130204_1664.el6.1.i686
sope49-mime-4.9-20130204_1664.el6.1.i686

Comparing this to the packages listed on the download page for CentOS6 I notice one difference:

I have sope49-cards-2.0_20120418-1.centos6.i686 when what is available on the download site is sope49-cards-2.0.4b-1.centos6.x86_64.rpm. I guess I have updated the servers at some point to use a nightly package and then have forgotten about it.

I upgraded to the sope49-cards-2.0.4b package and the problem appears to be solved.

Thanks for pointing me to the right direction.