Error in page when login component is removed

When I remove a log on component from the default page - it does not display the page and gives an error message:

"Object reference not set to an instance of object"

I have also removed the corresponding control component - log.ascx

The page has a slide show, data grid and a log on - I need to retain the page without the logon

However it displays the page properly only if I remove the code in the data grid and photogallery.

ie if I remove this code for one column

<%# IsNew(DataBinder.Eval(Container, "DataItem.NewFlag"))%>

I need the data and photogallery to be displayed on the page

How do I configure that again?

Any input is appreciated

Thanks