I have identified rollback status client from SEPM and then done the following activities on afftected system:
-- Repaired SEP.
-- Copied new unmanged SEP client package into local system. (C:\SEP\SEP32bit12.1.2Ru2)
-- Execute setup.exe.
-- Setup interrupted with the same error code.
-- Run Cleanwipe which successfully done after reboot.
-- Run same setup and installed unmanaged client.
-- Replaced sylink from SEPM.
-- Traced the same client from SEPM and found the same rollback icon with same status.
-- Delete client entry from SEPM.
-- Traced client after few min and found the client is online and reporting successfully with no more error status.