exp / imp is by no means the most flexible (or correct way) to upgrade a database.

Run the upgrade assitant program (will be in the start menu -> programs) area and it will do it for you.

you sure you did a full export then? at the top of an export file you should have stuff like this

Code:
CREATE USER "ANONYMOUS" IDENTIFIED BY VALUES 'anonymous' DEFAULT TABLESPACE "XDB" TEMPORARY TABLESPACE "TEMP" ACCOUNT LOCK