ORA-00382: string not a valid block size, valid range [string..string]

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ORA-00382: string not a valid block size, valid range [string..string]
Cause: User specified a value for db_nk_cache_size where n is one of {2, 4, 8, 16,
32}, but nk is not a valid block size for this platform.
Action: Remove corresponding parameter from the "init.ora" file and restart the
instance.