#Name? error, but only sometimes (1 Viewer)

[Gram123]

Hi.
I have a data entry form that contains price boxes. There is a total box, which simply adds these prices together with the control source
=Sum([Price 1] + [Price 2] + [Price 3])

This works fine. However, when I go into design view and save changes, the total stops working and displays #Name?. The only way to reset this and make it work again is to close the database down and re-open it.
I've tried using Forms![Form Name] preceding the sum, but this doesn't work either.

Any idea why this happens and more importantly how I can stop it?

 

[ntp]

Hello Graham,

You can try wrapping the Val Funcion around you references to the textboxes.
e.g. Sum(Val([Price 1]) + ...

ntp