Hi,
Please try this, go to Tablix Properties -> General Tab -> Row Headers -> Repeat header rows on each page(Check this textbox).
Also, in your groups, click on the parent group, and in the Column Groups(the right pane), select Advanced Mode. Now select your Parent Groups Static row and press F4.
The properties tab will appear, and in the properties tab, set KeepWithGroup = After and RepeatOnNewPage = true.
For more, refer to this link :
http://social.technet.microsoft.com/wiki/contents/articles/19398.ssrs-how-to-repeat-headers-on-each-page.aspx[
^]
Hope this helps !
Regards,
Praneet