mark on plotted paper - font setup before plotting!?

hello!

somehow on my plotted drawing i have a "mark" (wide and long line).

after i setup all for plotting and i hit PLOT, AC ask me to setup FONT.

size and colour of this "mark" depend on selected size and color of font.

Some sort of plotter watermark maybe?

i'm not shure!?

here is the picture of this mark (it is thick line instead some text).

i'm always asked for changing the font after i start print command.

and one more thing that appears in corners of the paper is vertical lines that represent margins (i think!?).

i didn't have those lines before.

one more thing...this only happens on HP designjet 500 printer and only on my computer in office.