Repeater inside a Repeater

[Microsoft]

Hi im an tryign to use a asp:repeater inside another asp:repeater

the problem I am having seems to be that the second repeater is not
recognised as a true control when placed inside the main repeater.

The data bind function Item_DataBound returns this error

Object reference not set to an instance of an object.

when i remove the inner repeater outside the item template it works...

Can anybody help me.. it is doing my head in.

I want to produce a list contained within a list item.