[Oracle] [ORA-30012] undo tablespace 'sample' does not exist or of wrong type

Change the informations in the pfile :
- c:/app/administrator/product/11.2.0/dbhome_1/database/spfileorcl.ora

- create spfile from pfile

Compilation succeeded then restart server :

- shutdown abort
- startup nomount
- alter database mount
- alter database open