Error 1:
In Xara X1 I opened a Xara X drawing which has 3 background layers. In X1 the layers weren't background layers anymore but they still didn't print on paper - that was pretty confusing...

Error 2:
In my drawing there is a "{" which is rotated 90 degrees. I had to turn it upside down and used the "Flip vertically" button. On screen it looked good, but on paper it was printed in the wrong place. Instead I rotated it further 180 degrees and that worked both on screen and paper.