Getting error while implementing webservice

HI ,
I’m new to using webservice descriptor as a Provider, I just wanted to learn to expose existing flow service as a webservice , hence installed the DocLitWebServiceExample_71 provided by Mark [],I changed the address field and run the createorder webservice but I’m receiving following error
Server logs
2400]2010-10-01 14:01:45 CDT [ISC.0088.0001E] SOAPException: [ISS.0088.9133] Error while encoding RPC output
[2399]2010-10-01 14:01:45 CDT [ISC.0088.0024I] Encode input (NSRecord): {n=createOrderResponse;t=2;d=0}[ref:]
[2398]2010-10-01 14:01:45 CDT [ISC.0088.0024I] Encode input (IData): >>>BasicData:ResponseStatus=>>>BasicData:ReturnCode=0000,ResponseMessage=>>>BasicData:Code=OK,Severity=Info,Description=OrderID 123 created successfully<<<<<<<<<
[2397]2010-10-01 14:01:45 CDT [ISP.0090.0004I] example71.provider.flow:createOrder – Successfully created OrderID 123 of type Test with initial date 2010-10-01T18:57:47.859Z
[2396]2010-10-01 14:01:45 CDT [ISP.0090.0004I] example71.provider.flow:getOrder – Reached createOrder
Error Logs
example71.provider.flow:createOrder java.lang.NullPointerException
pub.client:soapClient [ISS.0085.9281] Http Error: 403 - OK
I have installed the SOAPSonar Personal Edition and called the same service then I’m getting below error message. Just after the
Error while encoding RPC output
Please let me know if I need to make any change in the IS setting . I’m using webMethods version – 7.1.2

Thanks for your help!