Calculated field returning #Error!?...

[Carpetwarehouse]

I have a Report (Invoice), which is based on a query. The query has two calculated fields in it [Quantity] - which multiplys the lengh and width fields and [Line Total] - which multiplys [Quantity] with [Unit Price].

I would like a total of the [Line Total] on the Invioce.

What i have done is created a text box and set the control source as =Sum([Line Total])

But all i get is a #Error on the Report output page!?

Im sure this is an easy fix for someone on here.

 

[Carpetwarehouse]

Ahh i think ive solved it, i was using page footer instead of report footer!!