that file was created in Actionscript 1. i would avise to not use that at all. creating a sliding panel is not very hard to do in Flash, especially if you take advantage of a tweening engine such as the excellent Tweenlite by greensock ( http://www.greensock.com/tweenlite/ )
here is an example of a 3 panel slider that i made a while ago as an explanation for someone else. feel free to look at it and use it/modify it as you like. it was a horizontal slider which i now just adopted to a vertical slider for you.
there are of course many ways to approach every project. for this one i chose a simple path to our goal. each panel is a separate movieclip symbol. you can freely incorporate text, images etc into whichever panels you choose.
position the 3 panels in their 'closed' position. a mask layer is used to only show the area desired.
in my example i have the panels automatically tween in to their initial position - just for effect's sake.
then, clicking on any of the panels causes them to move in or out of their correct position. simple "if/else" statements check for the right conditions, and move the correct panel(s) accordingly. i kept all the functions broken out separately for maximum understanding of the logic. once understood, it could be collapsed to make the script more concise. not necessarily more effective, just more concise.
I now only have just one question; Can you tell me how to add another panel? I tried to add another movie clip. Basically I changed the instance name to "d" and added some codes like "d.addEventListener(MouseEvent.CLICK, changePanelsD);"but I get this error:
"Access of Undefined property ChangePanelsD"
it would seem that you didn't actually write the function "changePanelsD" to relate to the event listener.
adding a fourth panel now also necessitates changing the code - the y positions of all the panels in the 'opened' position. also, each previous function "changePanelsA, B and C" need to account for these postion changes, AND they also now have to include values for the fourth panel
this is the point where re-writing the code more concise could help keep track of the logic. by collapsing those four functions into one, and using a 'switch' statement rather than all those " if/else " statments it can keep the code neater and easier to read as the amount of items to keep track of expands. but that is a personal choice, and doesn't necesarily effect the working of the code .