problem solved ..
I was using jdk1.5 , i changed the same to jdk1.6 and got solved .
Another thing , my jdk installation was inside program files directory. I did new installation at C:Jdk1.6. Pleas note there is a space in Java_home when u are using Program Files as Directory.
Now my doubt is whether is it must that we need a JDK1.6 for jde versions 4.6 later ?
Any how thanks to all!!