Why do you have so many spaces in the address? Get rid of the spaces and then in the print preview mode click on the check to enable the grid and then double click where you want the address and the program will adjust position offset on the main window for you
From what I can tell your printer isnt liking the custom size. Is the size under the printer supported ones? The ones that says printer supported are the ones that windows reports that the printer can handle.
To use custom sizes it all depends on the printer driver itself on if it will work. At the bottom of the window you will see it says you have to use the post script printer drivers in order to use the custom size. Since you changed OS, your printer driver also changed.
Shane