none of the filter classes were supported until fp 8.
Yes, I accept. But, I want to know, "how shadow effect can be given in Flash 5?"
copy the graphic, and paste it with an offset of say 5px to the right and 5 px down on a layer below the original graphic. fill the copy with a black fill.
If it is a shape that you know you can create a shadow in a graphics program like Photoshop, save it as a png, and then import it to Flash.
If you are doing something like a dialog box with round corners and straight edges you can chop up the png for straight parts and the rounded corners and then using rotation and scaling only use two little bits for the shadow.
There are many, many tricky ways that people have learned to fake it over the years. Only limited by your creativity and your artistic skills.