Hi Gourav,
Considering your version check below SAP notes:
1913229 - Report /SAPAPO/DM_PEGKEY_REORG does not complete in background mode
1035516 - /SAPAPO/DM_PEGKEY_REORG takes a long time to execute
1411750 - Runtime error during execution of /SAPAPO/DM_PEGKEY_REORG
If above doesn't help let us know the details of the message or error you get.
Regards
Rahul