Hi Ravi,
Which PI version you are using?
Did you update the java version recently?
what is your current java version?
--> try to delete old JNLP files [Temp]
control panel --> java -->
Check if you are using the compatible jdk version.
Please refer the below links
Troubleshooting PI ESR and Integration Builder Logon Issues - Process Integration - SCN Wiki
http://wiki.scn.sap.com/wiki/display/XI/Troubleshooting+PI+ESR+and+Integration+Builder+Logon+Issues
Regards
Bhargava Krishna