Here is a simplified version of the situation. I just got this one this morning. It only involves one table in the query. Here is the SQL and the tag indexing sequence following it:

SELECT VideoPreview.Numero,VideoPreview.NoVideo,VideoPreview.Url FROM VideoPreview;
 WHERE VideoPreview.NoVideo=21 AND VideoPreview.Free

USE VideoPreview EXCL
DELETE TAG ALL
INDEX ON DELETED() TAG DELETE
INDEX ON NUMERO TAG NUMERO
INDEX ON ADDUSER TAG ADDUSER
INDEX ON ADDDATE TAG ADDDATE
INDEX ON MODUSER TAG MODUSER
INDEX ON MODDATE TAG MODDATE
INDEX ON NOVIDEO TAG NOVIDEO
INDEX ON Free TAG Free
USE

The only thing I see that could conflict and which is generic to all the tables is the DELETED(). I do have the tags on Numero, AddUser, AddDate, ModUser and ModDate on all tables however.