Thank you for your help. I don't have the C:\Program Files\Java\jdk1.6.0_11\bin\java.exe in my machine.
I checked and found that the SQL Developer I have use Java 1.6.0_11 which is same as you have mentioned. I have the path
"C:\Program Files\Java\jre7\bin\java.exe" in my machine. When I enter this path, there is a message say Cannot find J2SE SDK installed at path.
Does this mean that I need to install java 1.6.0_11 ?