My #10 envelopes come out with the addressee 3" from the top and 5" from the left; the sender is 1-1/2" from the top and 1" from the left. What am I doing wrong?

I am using Apache 4.1.1 (English; Microsoft)

(1) Do you have designed the page layout manually or do you have used any of the wizards? (2) Please try not to use #10 from the preset formats but define a user format, which is a little bit smaller than #10. (3) Do you have set the paper format explicitly in the printer properties? (4) Do you really use Apache OpenOffice? I ask, because “ask.libreoffice” is a LibreOffice service.