All you need to do is place an empty container with a name and the tubular widget in the page, then define the tubular widget properties for example:

container name = youtube

Tubular propertie elementid = youtube.id

Tubular propertie videoid = videourl

I have one Web Block with contains the js and the tubular code, and the video stay in front of the login form.

try to add this style: 

SyntaxEditor Code Snippet

.Login_Box {
    z-index: 2;
}

Also could you check if, without the style, you have the same problem in diferent browsers, like ie, chrome, firefox?

Thanks.

Add in the style of login...

do not work this soluction

It seams that you have something in your CSS that is changing the tubular functionality.

i already can put this working