Can you specify the version of Campaign that you are using, and provide some more details about where this is happening? Is it a delivery that is part of a workflow? Is there any special field in the content of the email?
If you have some screenshots to share too, that can help.
Looking at the error it looks like the template/delivery you are trying to preview has been previously used in a workflow etc. The reason is the table "wkdlv_1666572_399fe" only comes when a delivery has been analyzed and is the name given to the temporary table created during delivery analysis. Now after the delivery analysis this table gets dropped and no longer available in the DB.
Please make sure , you have not copied this delivery from another workflow and then trying to preview it.Also , try and create a new delivery from scratch and then try to preview it and it should work fine
I have tried creating a new delivery template and I still get the same error while I do the preview. Also I could notice that any out of the box template in AC if I try to preview also I get this error.