MACROMEDIA FLASH MX 2004-USING FLASH Use Manual page 129

Replace
5.
instanceName
Increment the scroll property by 1 to scroll the text up. The code should look like this:
6.
instName.scroll += 1;
Select the Down button on the Stage.
7.
Repeat steps 4 and 5.
8.
Decrement the scroll property by 1 to scroll the text down. The code should look like this:
9.
instName.scroll -= 1;
with the instance name of the text field you want to scroll.
Creating scrolling text 129