ORA-01445 cannot select ROWID from a join view without a key-preserved table

Cause: A SELECT statement attempted to select ROWIDs from a view derived
from a join operation. Because the rows selected in the view do not correspond
to underlying physical records, no ROWIDs can be returned.

Action: Remove ROWID from the view selection clause, then re-execute the
statement.

Sounds fairly self explanitory..