Support Team replied the topic: ERROR: OWNER NOT FOUND (310) / User Profile Sobi
No, the issue is related with user retrieval. It can't get the user object. It may be caused by an SobiPro-JomSocial inconsistency.
If you update to the latest version, we can check the error and source code (in fact, this error is not longer present in the current version). As you are working with an unsupported version, we can't check it.