wait a mint...
You mentioned that you are using windows installer and you are trying.
java -D64 -jar wls_121200.jar
How it can extract...... In windows you are not support to keep -D64 option... remove it and run it.
java -jar wls_121200.jar (If you are using 12.12 then keep Xms and Xmx option there to make it work successfully )
Make sure you have installed a 64bit JDK.
When you run java -version command on a 32bit JDK you will see the following :
java version "1.7.0_15"
Java(TM) SE Runtime Environment (build 1.7.0_15-b33)
Java HotSpot(TM) Client VM (build 23.7-b01, mixed mode)
For a 64bit JDK you should see the follwoing output :
C:\Program Files\Java\jdk1.7.0_51\bin>java -version
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)
Make sure you are using a 64bit JDK and run the following command and it should work fine :
java -d64 -jar wls_121200.jar -log=error.txt
If you get any errros, check / upload the contents of error.txt file to understand why it is failing.