The count of the request during Load Test is not increasing!!!

hi,

while executing as web service load test with one single request the count of the request is not at all increasing. The count(cnt) is increasing only to the thrad count and except that the count of the request is not at all ramping up.
Can anyone suggest me a method to perform a Scalability Load test with ramp up of users from 1 to n in number?

Also when trying to capture few parameters from response and transfer the same to Datasink we are getting JavaNullpointer Exception.
Please find below the steps of my project:

We tried to import test data(i.e year) using Excel-->Property Transfer-->Request-->Property Transfer-->Log Groovy-->Show result Groovy-->data Sink-->Loop.

My scripts is failing in Show result Groovy.

And when i do a load test the whole script is failing and the error message from the error log is as follows:

ERROR [errorlog] java.lang.NullPointerException
java.lang.NullPointerException
  at jxl.write.biff.File.write(File.java:147)
  at jxl.write.biff.WritableWorkbookImpl.write(WritableWorkbookImpl.java:697)
  at com.eviware.soapui.impl.wsdl.teststeps.datasink.ExcelDataSink.finish(SourceFile:159)
  at com.eviware.soapui.impl.wsdl.teststeps.WsdlDataSinkTestStep.finish(SourceFile:192)
  at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCaseRunner.run(WsdlTestCaseRunner.java:262)
  at com.eviware.soapui.impl.wsdl.loadtest.WsdlLoadTestRunner$TestCaseRunner.run(WsdlLoadTestRunner.java:401)
  at java.lang.Thread.run(Unknown Source)"





Can anyone suggest how can i overcome these issues?

Thanks in Advance


Regards
Sree Satya