Hi Sergi,
1) The PCM Data Loader tool stores it's activity log in a specific database table called PPLOAD_LOG for you to read.
2) When you populate staging tables, you actually have to distingish between values... for example PPLOAD_ACTIVITYDRIVERVALUE
Please read through the PCM Database Administrator Guide, which has a Data Loader section and can be found on http://help.sap.com/bopcm