Did you try to change the printer driver?
How do you "move the right margin" ?

>I have an application that uses a standard Fox report layout to print onto a form that is C5 envelope in size.
>On this printer only, I do not appear to be able to move the right margin sufficiently to have the data land in the correct boxes.
>I am using a Vista PC and connecting to the printer via Wireless.
>I have no issues with any other printer.