I would say that sounds like a Netezza setting, possibly by the admins to keep accidentally large requests from processing.
Talk to the DB admins and see if this is the case and what settings you may need to have set for your access.
Also, it is good idea to include the entire text of the Errors and better to include the code that generated them. Copy the text with code, errors, notes, and messages for the problem call. Paste into a code box opened on the forum with the </> icon to preserve formatting. Errors often include diagnostic characters but the message windows on this forum will reformat text resulting in the characters appearing in the wrong place.