[Javascript] why doesn't this work in IE 6 if it works fine in 5.5?

[Naomi]

Hi,

this is my first time posting, and i do need help!

I have a webpage that is essentially a slideshow of images.  The code works
just fine in IE 5.5 on both Mac and PC.  However, it doesn't work on IE 6.
The same is true for the NN versions of my files.  They
work for NN 4, but not 7.

so i wonder if anyone can tell me what has changed in the new browsers that
makes this code non-functional?

I've pasted below the parts of the code that I believe is the problem for
the IE version of the file.

The url for this page is:
http://www.painterlypixel.com/ppportfolio.html

Thank you so much for any input!
Naomi

There are two functions that control the display of images.  The first is
attached to grahics  (arrows) that move you forward or back, keeping track
of a variable  "num".

The second is for additional images related to the current image, by
clicking on text (numbers for each additional image).

NUMBER ONE: 

//changes the images and the descriptive text which is in the span called
//"description". also used in the ChangeImage() and PrevImage() functions

function ChangeList(){
              document.form1.IMG1.src = imageArray[num].src
              document.all.description.innerHTML = textArray[eval(num)]
  }

//changes the images using the next button
        function ChangeImage(){
           num=num+1
           if (num>12){
           num=0
            }
              ChangeList()
  }

//changes the images using the back arrow
function PrevImage(){
            num=num-1
           if (num<0){
            num=12
        }
            ChangeList()
   }


THIS SECTION displays additional images for each project.

var sample 
var project 
var text
//changes the Sampleimages and text.  This changing text is the span called
"screenshots".   why doesn't the commented out line work?  i tried that
first.

function ChangeSample(project, sample, text){
//        document.form1.IMG1.src = eval("\"test/" + project + sample +
".jpg\"")
        document.form1.IMG1.src = eval(project + sample + ".src")
        document.all.screenshots.innerHTML = screenshotArray[eval(text)]
  }