JAVA Virtual Machine launcher Error during IPS 4.0 SP4 installation

Hi,

I had IPS 4.0 SP2 and DS 4.0 SP01 in Windows 2008 server. To upgrade to SP04, I uninstalled the Data services and then IPS, it went good but during uninstall got a message on Java virtual machine launcher.

Now im trying to install IPS 4.0 SP04, but I got lot of Java virtual machine launcher messages and at last it got stuck saying

"JAVA Virtual machine launcher

    Could not find the main class

     Com/businessobjects/sdk/biar/utility/XSDUtility. Program will exit"

Now i could not continue the installation or Uninstall it either. I do see it is because of Java version mismatch( i had 1.6.0.19 already in the server before installing)

Is there a solution for this other than reformat the OS? that would be the last thing that i would prefer to do. Please advise.

Thanks in advance