+9  A: 

Try setting your wmode = transparent on the flash. This will keep flash from laying over top of everything no matter what z-index you set it to.

jacobangel
+1  A: 

You could try to paste some of your CSS code at w3schools TryIt Editor to check if it is correct and z-index works as you think.

schnaader
The upvote was for fixing my image :)
fmsf
Thanks, at least I could help with that ;)
schnaader
A: 

While wmode=transparent will work, it causes quite a performance hit. You'll probably get better results with wmode=opaque.

Ms2ger
A: 

What if you can't change the flash modes because it's a banner from a network like AdSense?

create a question with that if you wish to know the answer
fmsf
+1  A: 

Remember that you need to set the wmode parameter separately for IE and other browsers:

<param name="wmode" value="opaque" /> <!-- for IE -->
<embed src="images/banner/banner.swf" quality="high" wmode="opaque" ... <!-- for other browsers-->
Kaz Fernandes