Hi Ashwini,
it seems like you use old jar-Files and updated the wrong ones from note 1035436. The error happens in JNetAppsWDAProductiveS.jar. Since you have to use NW 7.40 with PPM 6.1 please use the attached jar-Files of note http://service.sap.com/sap/support/notes/1926137. This note contains also the renewal of certificates for JNetAppsWDAProductiveS.jar.
In the exception screenshot of the JNET-Runtime you can see the JNET-version 1.1403.
The newest JNET-version might be - as for last week - JNet 1.1410.15295
br,
Peter