Invalid text representation on file_managed query

I'm trying to get nivo_slider to work ... installed the module, installed the libraries from http://dev7studios.com/plugins/nivo-slider, made sure jquery update is set to 1.7, then click on 'configure' for nivo_slider, and I get the message below ...

-

Warning: array_flip(): Can only flip STRING and INTEGER values! in DrupalDefaultEntityController->load() (line 173 of /usr/local/www/drupal-7.22/includes/entity.inc).

Notice: Trying to get property of non-object in nivo_slider_slide_configuration_form() (line 72 of /usr/local/www/drupal-7.22/sites/all/modules/nivo_slider/nivo_slider_slides.admin.inc).

PDOException: SQLSTATE[22P02]: Invalid text representation: 7 ERROR: invalid input syntax for integer: "" LINE 4: WHERE (base.fid IN ('')) ^: SELECT base.fid AS fid, base.uid AS uid, base.filename AS filename, base.uri AS uri, base.filemime AS filemime, base.filesize AS filesize, base.status AS status, base.timestamp AS timestamp FROM {file_managed} base WHERE (base.fid IN (:db_condition_placeholder_0)) ; Array ( [:db_condition_placeholder_0] => ) in DrupalDefaultEntityController->load() (line 191 of /usr/local/www/drupal-7.22/includes/entity.inc).

-

the above PDO/Statement translates to the database as:

==
SELECT base.fid AS fid, base.uid AS uid, base.filename AS filename, base.uri AS uri, base.filemime AS filemime, base.filesize AS filesize, base.status AS status, base.timestamp AS timestamp
FROM
file_managed base
WHERE (base.fid IN (''))
==

the problem is that base.fid is an integer value, and '' denotes a character value:

ERROR: invalid input syntax for integer: ""
LINE 4: WHERE (base.fid IN (''))

Database backend is PostgreSQL, Drupal version is up to date as of today (7.26), nivo_slider is the latest dev version ...

Help?

Thanks ...