Multiple query post pagination in taxonomy page.( 404 )

Hi,

I have parent term and child terms.
In parent terms page, i have query all post of its child terms.

post_per_page = 2

Parent
Child 1 ( 2 post count )
— pagination —
Child 2 ( 4 post count )
— pagination —
Child 3 ( 10 post count )
— pagination —

And the pagination for page [3] and up gives me a 404 page.

My plan to add ajax for the pagination because it’s a multiple pagination in single taxonomy page, but i can’t proceed because of the 404 result.

Can you please help me on this one..

Thanks

http://wordpress.org/plugins/wp-pagenavi/