Hi Siddhartha,
If its something you are trying directly in Dev, Give the below method a try.
1. Put a logic in your workitem exit so as to put it in infinite loop.
2. Have a logic inside it so that you can come out of infinite loop.
3. Launch your debugging from SM50 Transaction.
I think you will get some idea as why it is failing if you try this.
Hope this helps.
Thanks
Tirthankar
