Btukfyl

I am combining code from few questions to obtain changing logo-picture in position of footer. Answers involved are those:
Place a TikZ picture on every page, How to use pageref{foo} as a number?

and maybe some more.
Using informations in those I produced code, simplified for posting here (original picture is bit more messy, but there should be everything).

Trouble is within line with shifting scope, where I refer to page offsets (as they are defined in previously mentioned questions), but failing in code compilation. I expect, that its because I am giving wrong data type to scope shift operation.

How can I fix that?

Here I present simplified (not compilable!) code:

documentclass[12pt]{book}

usepackage[usenames,dvipsnames,x11names]{xcolor}

usepackage{lastpage}

usepackage{refcount}

setrefcountdefault{1}



usepackage[all]{background}

usepackage{lipsum}



usepackage{tikz}

usetikzlibrary{arrows,calc,snakes,shapes}



newcommand{nuclei}[1]{%

  shade[ball color=white] (#1) circle (.4);

}



newcommand{nucleus}{%

  nuclei{0.1,0.3}

  nuclei{0,0}

}



%electron{xwidth,ywidth,rotation angle}

newcommand{electron}[3]{%

  draw[rotate = #3](0,0) ellipse (#1 and #2)[color=blue];

  shade[ball color=Black] (0,#2)[rotate=#3] circle (.2);

}



usepackage{changepage}

strictpagecheck



newcommand*{VOffset}{2cm}% vertical offset

newcommand*{HOffset}{1.7cm}% horizontal offset



newcommand{MyTikzLogo}{% For a logo drawn with TikZ

begin{tikzpicture}[remember picture,overlay,scale=0.2]

 checkoddpage

    ifoddpage

        begin{scope}[shift=(HOffset,-paperheight+VOffset)]

            begin{scope}[rotate=360*thepage/getpagerefnumber{LastPage}]

                    nucleus

            end{scope}



            electron{1.2}{1.4}{260+(360*thepage/getpagerefnumber{LastPage})}

            end{scope}

else

    begin{scope}[shift=(paperwidth-HOffset,-paperheight+VOffset)]

            begin{scope}[rotate=360*thepage/getpagerefnumber{LastPage}] 

                    nucleus

            end{scope}



            electron{1.2}{1.4}{260+(360*thepage/getpagerefnumber{LastPage})}

            end{scope}

fi

end{tikzpicture}

}



SetBgContents{MyTikzLogo}% Set tikz picture



SetBgPosition{current page.north west}% Select location



begin{document}



section*{Lorem Ipsum}

lipsum[1-25]



end{document}