DHTML/Javascript Absolute positioning

here is the page of the test piece I am working on http://www.firelegend.com/DHTML/fnm.htm

If you rollover the large "F" in the graphic a layer apears with a login.

The problem -
It functions just fine, but my issues is that I understand that the Layer has to have absolute positioning, ie. 200 pixels from the left.. 500 from the top.. or something like that, but the actual image that I have it on.. the image (screen shot of a flash file) I would like to be be in 100%X100% table and I would like it aligned middle/center. Right now it is aligned top/left. If I align it middle/center, it breaks.

Why does that break it? How do I fix it? Any clues?

It is fine by me if the login pop up has to be absolute.. but I need the FlashFile/ScreenShot to be centered..

What do you mean "it breaks"?

I thought it broke but it didn't, my B. Turns out it wasn't broken, I thought when i centered it it no longer worked, like the layer didn't turn on.. I have to much to do today, like 5 projects at once, a flash randomizer, DHTML scroll that works like a iframe and then this dhtml stuff for the company login, I am going bonkers and having a hard time concentrating when people come at me and ask me to come to there desk to dissucse one of the saiod things, so I get all outa wake and am unable to concentrate, not to mention the company has gotten larger and more people like to conveine aroun desks to chat about projects, sports and code, so I have to turn my headphone volume way the freak up to not hear them.

Yeah I know I type shiety.

**end rant**

so yeah, it does work, I just wasn't paying enough attention.. so er.. uh.. nevermind? heh.. opps..