regarding lead selection?

i m getting this error when i clivk on one button.

how can i resolve this

Error when processing your request

Note

The following error text was processed in the system CGD : The lead selection has not been set. NURSING

The error occurred on the application server cgslsvr3_CGD_20 and in the work process 0 .

The termination type was: RABAX_STATE

The ABAP call stack was:

Method: RAISEELEMENT_NOT_FOUND of program CL_WDR_CONTEXT_NODE===========CP

Method: PATH_TABLE_GET_ELEMENT2 of program CL_WDR_CONTEXT_NODE===========CP

Method: GET_BOUND_ELEMENT of program CL_WDR_VIEW_ELEMENT_ADAPTER===CP