Opaque DIVS in FF and IE

Hi all - I have a scenario where I want to overlay content in a
dIV over a BG image. The DIV needs to eg have 50% opacity. I have managed to figure it out, but Im not sure if someone can improve the code, or tell me why IE gives an ActiveX block on the page. Are DIV filters considered ActiveX?

please have a look here at what I have done, and tell me if there are issues in FF, IE, Opera etc, and any way to improve the code / approach.

Muchos gracias. Pix.:moustache