Inserting a manual page break splits the table. Heading rows do not repeat, and the table cannot be selected as a single table. Formatting the row as "Page break before" (on the Line and Page Breaks tab of the Paragraph dialog) will break the table to a
new page without splitting it.
To correct the existing situation, you'll need to delete the page break. You should then be able to delete any text paragraph that still splits the table.