Unable to Connect SAP RFC using jrfc jar

Hi Experts,

I am unable to connect SAP ISU RFC using jrfc.jar. I have download the the jrfc.jar from the server.But when I write a java class to connect the rfc using jrfc.jar and export that java class as .jar file and run that file into the server but it's unable to connect.It showing some error.

But same code when i am write in the NWDS 7.0(Web dyn pro Application) its running fine.

But I have build a java class and export as a jar and run through the server using cron job.Because that class communicate with the sap and an rfc return some data and based on that i have to send mail to some people in daily basis.

Please help me regarding this.

Thanks and Regards,

Amit Basak