Corel Painter X: Palette knife problem

I am having a problem with all but the tripple rake palette knives. I
am using an windowsXP machine, a WACOM3 tablet and a 6d pen. I get a
full width stroke with vertical strokes and variable width narrowing as
they approach horizontal. A horizontal stroke produces a thin line.
This occurs no matter how I hold the pen. I have tried all sorts of
settings in the General and returned to default. Nothing changes the
outcome. In various books and Painter magazine I see examples of
palette knife strokes going in different directions but Iam unable to
duplicate the strokes I see in the books.

Does anyone have an idea as to what might be causing this problem and
how I might be able to fix it?

Thanks in advance for any help with this matter.

By the way, I am attempting the "Speed Painting Tutorial in Issue 11 of
Painter Magazine on Page 62 (the stroke, Loaded Palette Knife) is
illustrated on page 67 in the Brush Selection box