adamng,

I'm sure you've performed a full backup before you updated the PROPS$, so Halo's sugestion might sound a little drastic ;-))

Serriously, if you don't have the backup your only option is to create a new database. Changing character set the way you've tried was quite popular among dba's in the past, however it was also well known that it is totaaly unsupported and that if you do a typo you can say bye-bye to your database. It seemed you've learned it the hard way.

In 8i (or was it allready in 8.0?) Oracle introduced a new ALTER DATABASE option:

ALTER DATABASE SET CHARACTER SET new_charset. That way Oracle prevents you to specify a wrong name for the characterset. Nevertheles, Oracle still recomends a full backup before you perform this operation.