Components and applet not loading when running the application using JVM1.3

I have my UI written in JavaScript.When I click a button,it opens a window showing the different components(images) and an applet containing a tree structure.The applet code is written in java
This is working fine and the applet is loading properly when I use JVM1.4. But there is a problem when I use JVM1.3.1_09.The images appear broken and the applet doesnot load.(When I click on one of the broken images,the images appear correctly but the applet still doesn't load)
Can anyone tell me what could be the reason behind this behavior??
My sys config: win2k-SP4, IE5.0-SP4


If you are using SDK 1.4 for compilation,
recompile your classes with the option -target 1.1
javac -target 1.1