iSync exception when importing contacts from server to Mac

[mbarbieri]

Hi,
I'm trying to sync contacts between Zimbra server and Mac (Snow Leopard) using iSync (5.0.17_GA_2957).
iSync doesn't add any contact in Mac, and this happens only with a particular Zimbra account, importing other people's contacts works fine.

Logs show this (please tell me if you need more log lines):

[Fri Sep 25 14:56:08 200] pushing new contact [] (1213)
[Fri Sep 25 14:56:08 200] Caught exception while trying to sync: name = NSInvalidArgumentException, reason = *** -[NSCFDictionary setObject:forKey:]: attempt to insert nil value (key: value) (1213)
[Fri Sep 25 14:56:08 200] cancelling sync (1213)
[Fri Sep 25 14:56:08 200] [assert] error: !contactErr
[assert] where: "ZimbraHelper_main.mm", "Sync", line: 1042
 (1213)
[Fri Sep 25 14:56:09 200] mode is refresh sync (1213)
[Fri Sep 25 14:56:09 200] pushing xxx@xxx.com with record {
    "com.apple.syncservices.RecordEntityName" = "com.apple.calendars.CalDAVAccount";
    displayName = "xxx@xxx.com";
    isAutoDiscovery = 0;
    login = "xxx@xxx.com";
    order = 1;
    principalURL = https://xxx.com:443/principals/users/xxx@xxx.com/;
    refreshInterval = 1800;
    useKerberos = 0;
} (1213)
[Fri Sep 25 14:56:09 200] committing changes (1213)
[Fri Sep 25 14:56:09 200] finished syncing (1213)

Thank you for your help,

bye