>The target database is a 2.6 database.
>It does not have any key fields in it.

For the view to update, it must have a field marked as a key field.
The target table does not need to have an index on this field, but the field should be unique, since it adds to the WHERE clause "WHERE | AND keyfield = " - if it's not unique, it will update multiple records.

Insanity: Doing the same thing over and over and expecting different results.