z-index and div overlap issues

[buggslife]

Hey, after reading several posts here by SuzyUK I think I have solved some layout problems I was struggling with in IE6.

However, I still have two issues.

1) z-index in IE6
2) layout overlaps from mid column div over left div

Here is my development page:
[buggslife.com...]

1) The images/buttons on the left and in the main content do not appear in IE6 and I have tried various changes to the z-index including their parent divs.

PLease can anyone help on this?

The images in question are based on the code below (works ok in Chrome and FF):

 /* ------underscore l refers to landscape orientation --------- */
  
  .photo_l {
  margin: 4px;
  position: relative;
  width: 145px;
  height: 102px;
  float: left;
  font-weight:bold;
  padding: 0px 0px 0px 0px;
z-index:2;
  }
  .photo_l img {
  background: #fff;
  border: solid 1px #ccc;
  padding: 4px;
  z-index: 5;
  width: 100%;
  height: 100%;
z-index: 4;
  }
  
  .photo_l a {
  text-decoration: none;
  }
  
  
  .photo_l a:hover img {
  border-color: #999;
  }
  .photo_l em {
  width: 102px;
  background: url("http://www.buggslife.com/galleries/images/bubble.gif") no-repeat;
  padding: 3px 0px 0px 0px;
  display: none;
  position: absolute;
  top: -15px;
  left: 29px;
  font-style: normal;
  text-align: center;
  text-transform: uppercase;
  color: black;
  z-index: 6;
  }
  
  .photo_l a {
  text-decoration: none;
  color: #000;
  }
  .photo_l a:hover em {
  display: block;
  }
 
  
  
  /* begin gallery icons borders etc */
  
  .white_rounded_l span {
  width: 145px;
  height: 102px;
  position: absolute;
  top: 5px;
  left: 6px;
  background: url("http://www.buggslife.com/galleries/round-corner_s.png") no-repeat;
  z-index: 5;
  }
  .white_rounded_l img {
  border: none;
  padding: 5px 6px 6px;
  background: url("http://www.buggslife.com/galleries/round-bg_s.gif") no-repeat;
  z-index: 3;
 }

2) On smaller res screens or if you reduce the browser window size the col_mid overlaps the colleft...I cannot figure out why.
Any clues?

[buggslife]

I seem (fingers crossed) to have 'fixed' the layout issue 2).

However, I am stuck with the z-index problem...any ideas?

[buggslife]

Still really stuck on the z-index - any advice anyone?

[brokenbynubs]

Are you using any javascript for those images? On my IE6 I see a quick blink of images on the page before I get a JS error and they go away.