It may be the case that tables created during the first attempt as a part of the upgrade are still present and are hampering the real attempt to upgrade to v11.1
Work around:
Login into SQLPlus as protect, and:
drop table UPGRADER_ERRORLOG_V11_1_0;
drop table UPGRADER_PROGRESS_V11_1_0;
drop table UPGRADER_TRACKER_V11_1_0;
Restart the upgrader.