On upgrading Stages to newer versions there are many steps executed to modify the database. Below you'll find a variety of possible problems depending on your databse configuration and size.

java.sql.SQLException: ORA-30036: unable to extend segment by [size] in undo tablespace [tablespace name]

Depending on the size of the database, this exception can happen e.g. in upgrade step 5248. The tablespace from the exception has to be extended by the mentioned size.