After much research and trial/error, I think I found a solution...

Go to Start > Settings > Printers.
Select File > Server Properties.
Select Create New Form.
Type a name for your new form.
Enter the paper size of your form. You can also enter the margins if applicable.
Click Ports. Select the port to which the printer is attached.
Click Drivers. Select the printer driver.
Click Save Form.

Return to Crystal Reports. Go to Page Setup. Your new form should be listed in the drop-down list in the Page Options panel. It will set your horizontal and vertical dimensions to the same as you added on your new form. This will also keep the orientation correct (not changing between portrait and landscape).

Hope this helps someone else facing this problem.

Warmest regards,
Gilley Estes

Gilley Ann Estes
Senior Technical Writer
Welton USA