This blog post covers how to make changes to your existing SQL Server Reporting Services Report to ensure that the Column Headings appear at the top of every page. The steps (and screen shots) below come from Report Builder 3 running against SQL Server 2008R2.
Looking at a standard report the first thing you will have tried is to set the "Repeat Column Header" and "Repeat Row Header" on the table. For whatever reason this doesn't work and you'll then have found yourself here (probably via Google!);
This will then add in some of the "Hidden" levels in the Row Groups entry box;