SAP SRM - SM58

Hi Gurus ,

PLease answes all the questions below :

1. Could you please let me know in detail what is the function of SM58 transaction?

2. I exucuted this tcode in SRM system and found : Function Module - SPERS_SET_DISTRIBUTION_DATA , Caller - ECCRFC and error message saying 'A row with the same key already exists.'how do i Check what exactly caused this error ?

3. What action should be taken when we see errors in SM58 ?