[eluser]DimCI[/eluser]
Buddy, seems i've found this.
The problem (mine) was in my server options which concern the stuff like mime-types and folders' properties or something like this may be. well, in brief- relocate the f...g /captcha/ folder in your images folder and call it a day,lol. Now I have the path like this:
$config['DX_captcha_path'] = '../images/captcha/';
and it works
yet still have another problem with dx_auth on windows machine..