Pl post exact OS details, along with a link to the document you followed for the upgrade. Looks like your database files have the value "10.2.0" hardcoded in the file paths, which is always a bad idea :-)
One option is to rename the 10.2.0 datafile directories to something generic, then use the ALTER DATABASE DATAFILE RENAME clause to correct the location in the control file.
How to Rename or Move Datafiles and Logfiles [ID 115424.1]
For the control files, shutdown the database, rename the 10.2.0 hardcoded path to something generic, modify the init.ora file to reflect the new locations of the control file, then startup the database.
Pl ensure that you have a good cold backup before attempting this.