no mark where to put text

there is no marking that place you have to enter your info

you can see a screenshot here: pu-kit.shl-hosting.dk/screen.png

That's probably because of your template's CSS. Could you give us the URL of your website ? We would be able to tell what CSS to change to fix the problem.

my url is: pu-kit.shl-hosting.dk/index.php?option=c...ut=listing&Itemid=53

The problem comes from the CSS code:
#rt-main .inputbox, #rt-main input#email, #rt-main input#name, #rt-main input#username, #rt-main input#password, #rt-main input#password2, #rt-main input#passwd {
border: none;
}

which you can find in the file pu-kit.shl-hosting.dk/templates/rt_panacea_j15/css/template.css

If you remove it and flush your browser's cache, the problem should be solved.