Error : task TS999xxxxxx not defined as start/end event

Hi All,

Event ZFP05_BO LOT_POSTED for task TS99900410 not defined as start/end event.

where

ZFP05_BO      = BO

LOT_POSTED = event

TS99900410    = task.

Above mentioned Error I am getting in SWEL transaction. Even though my workflow getting completed and everything working succssfully, bcause of above error, a error message is generating in Business Workplace(SBWP) as "ERROR IN EVENT RECEIVER". See attachment below

If any one having any idea about how to solve this, please let me know.

Thanks.