Doc Manager issue

Hello,

while trying to assign some documents to an existing Document Group, I’m getting the following error:

MODx encountered the following error while attempting to parse the requested resource:
« Execution of a query to the database failed - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ’AND document = 20’ at line 1 »
      SQL: SELECT * FROM `loc_vsbtunew`.`modx_document_groups` WHERE document_group = AND document = 20



Does anybody know what the issue is and how to fix this.

Edit; please ignore or delete this entry - forgot to check a radio button

Thank you in advance for your help.