I'm trying to upgrade my ancient installation and am running into problems running the pgsql/2.2.3.9.config upgrade script.  To avoid problems with duplicate primary keys, I changed "PRIMARY KEY" to "UNIQUE" throughout the scripts.  However, I'm still getting an error at:

ALTER TABLE mp_moduledefinitionsettings
ADD CONSTRAINT pk_moduledefinitionsettings UNIQUE (id);
 

It says "could not create unique index".  I looked at the data and found two rows with the same ID:

mojoportal=> select * from mp_moduledefinitionsettings where id = 16;
id | moduledefid | settingname | settingvalue | controltype | regexvalidationexpression | featureguid | resourcefile
----+-------------+-----------------------------+--------------+-------------+---------------------------+--------------------------------------+--------------
16 | 11 | GalleryWebImageWidthSetting | 480 | TextBox | ^[1-9][0-9]{0,2}$ | d572f6b4-d0ed-465d-ad60-60433893b401 |
16 | 11 | GalleryCompactModeSetting | true | CheckBox | | d572f6b4-d0ed-465d-ad60-60433893b401 |
(2 rows)
 

Presumably this is due to some ancient bug.  What should I do to correct it?  Is the id column of this table actually used by some other table?

--Dean