Hi Srikanth,
I think Rick's suggestion of creating a new thread and supplying more details with your issue will get more responses.
Anyway, regarding your issue, you can try making a test program that calls SAP_WAPI_DECISION_COMPLETE and check if it will work, instead of just running it in SE38.
Please revert back with your codes if it still doesn't work.
Best Regards,
Dexter