Thanks Alex! I have checked records in KNTA_UPGRADE_RECORDS table, but its not providing any additional information.
Upgrade log shows that this issue occurs when 8.0 upgrade script runs 7.5_to_8.0 data model change script. It runs several scripts, but it failed during execution of "pfm/kpfm_score_selections_nls_800_5_1.sql" script.
BUILD FAILED - /ppm05/app/PPM/upgrade_800/xml/upgrade-75-to-80.xml:59: java.sql.SQLException: ORA-20011: ORA-20011: : : for reference code _RISK_DOMAIN_PFM_SCORE_TECHNICAL_RISK_NO_UNCERTAINTY ORA-06512: at line 1179
As suggested by this forum and HP support we have already disable Reference code flag to workflow tables before running upgrade script.