sub query in Start routine

Hi,

I need to use sub-query to check whether data exist in a table, if yes then delete. For that I am trying this code in Start Routine. It shows some weird syntax error - E:Method "" is unknown or PROTECTED or PRIVATE

DELETE SOURCE_PACKAGE WHERE CSM_CASE IN ( SELECT CSM_CASE FROM /BIC/AZDPM_DS300 ).

Any thoughts please.

Regards

Vikash