I use CalDAV-sync and CardDAV-sync, and have not had any problems syncing my phone with the data in Owncloud.
However, I think you are trying to import data from your phone into Owncloud. I have not tried this, and don’t know if the sync clients support this functionality.
Can you manually export the data from your phone, and use the Owncloud web interface to import the data into Owncloud?