PA_EVENT_PUB.create_event

Hi Team,
I am facing the below error while creating the revenue event using teh API PA_EVENT_PUB.create_event.

"The project name you have entered is invalid.". I tried my best to understand whats the issue, but not succeeded. Below is the code i am using .

 L_EVENT_REC.P_TASK_NUMBER           := P_TASK_NUMBER;
    L_EVENT_REC.P_PM_EVENT_REFERENCE    := X_PM_EVENT_REFERENCE;
    L_EVENT_REC.P_DESCRIPTION           := 'Revenue Event';
    L_EVENT_REC.P_COMPLETION_DATE       := X_EVENT_DATE;
    L_EVENT_REC.P_PROJECT_NUMBER        := P_PROJECT_NUMBER;
    L_EVENT_REC.P_BILL_TRANS_REV_AMOUNT := X_REV_AMT;