Drupal expert required

I need a Drupal 6.x expert to take a look at a Drupal database which is not working correctly.

We are using the node import module to import .csv files of our products to ubercart. The process of importing the products initially involves having to to clear out the content and then reimporting it. Part of the process is to FTP the images of the products to the website.

During the last attempt to import we started to see the following error at the Preview Import step of the import process (step 7):

Referencing to the file used in the Picture field is not allowed.

Changing the name of the image.jpg file and then making the same change on the picture field of the .csv file fixes it but we have over 14,000 rows to import so it isn't possible to change every file. We think there is some garbage left in the database from the last time we deleted all the content but I can't find where it is.

We've tried Googling the error but most of the fixes involve some PHP experience so I need a Drupal/PHP/SQL wizard to take a look and advise what to do.