If you are seeing this message displayed when you try to order a layout then this is because:

1. You have designed your layout as a Composite type AND

2. You have setup the price list for the same Layout as a Traditional Matted type.

If you wish to produce the final layout as Composite (with the images and mat together one piece of paper) then you need to change the type in your price list.

If you wish to produce the final layout as a Tradtional Matted type (with the image in each opening as a separate print) then you need to change the type of your layout.

For how to do either of these (or order this as a once-off), see this KnowledgeBase Article: Ordered Layout not in Composite section in Production