Re: coreldraw x3
According to Corel's help, crop mark printing requires .5" on each side for your paper size, which means your page size should be .5" less on each side. So in order to get an accurate print with crop marks, you should set your page size at 7.5" width, 10" height. Easiest way to change this is to deselect everything, you should see the page dimensions at the top now, just alter their values.
If you think of it this way, Corel prints what it sees normally, but with crop marks enabled, it has no way to ensure, for example, that you aren't printing a big black square over where it normally prints the cropmark. So to ensure that the page is printed as it is seen (albeit not properly sized), it resizes automatically to be able to fit in the cropmarks. When you have the page size and width adjusted smaller, it can print on the areas outside of the page layout because you specify the size of the paper.
Hope I didn't confuse ya there, I'm a bit tired heh, but adjusting your page size to 7.5"x10" should solve it for ya.