That's an Upgrade/Migrate that you are trying to do.
Find docs for 1ogr2 migration guide for proper guidance.
It is almost the same procedure as if you are cloning the db,
but during startup in the 10gr2 environment(include ORACLE_HOME/ORACLE_SID) you have to include
either "upgrade" or "migrate" option like:
sql> startup upgrade
and you have to run rdbms script like addpatch.sql depending
on what thus the readme.txt file suggest.