Pages cannot be automatically inserted because you are not paginating into a master text frame

This is displayed because the document is being paginated into the Master Spread. When paginating Into Text Flow text frames must be created on the master spread, threaded together and then overridden on Page 1. The frame can be overridden by holding down CMD + SHIFT (Macintosh) or CTRL + SHIFT (Windows) and clicking in the text frame a few times.

Once a flashing insertion point appears in the text frame it is then ready to be paginated into.
Error 1 - EasyCatalog Pagination Module