Hello Dany, it is likely that there is a record in one of the fields of the table UNI_EVT_EXTRACTIONS that UVC does not handle well...
Other thing could be that there are too many lines on that table ( more than 100K).
My advice would be to take a quick look of the table and see if something is odd. Then launch a Reporter Purge with a retention period that deletes the guilty line.
Example of the queries in Oracle if you want to do it manually:
delete from UNI_EVT_EXTRACTIONS where EXTRACTION_ID in (select EXTRACTION_ID from UNI_EVT_EXTRACTIONS l where l.STATUS<>'PENDING' and l.STATUS<>'RUNNING' and l.LAST_UPDATE_TIMESTAMP< to_date('2018-09-30 11:31:32' , 'yyyy-MM-DD HH24:MI:SS');
delete from UNI_EVT_LOG where LOG_ID in (select LOG_ID from UNI_EVT_EXTRACTIONS l where l.STATUS<>'PENDING' and l.STATUS<>'RUNNING' and l.LAST_UPDATE_TIMESTAMP< to_date('2018-09-30 11:31:32' , 'yyyy-MM-DD HH24:MI:SS');