The problem seems to be the fact that the EVENTDATADESC columns has some NULL entries, but I thought the line

IF V_EVENTDATADESC IS NULL THEN
V_LOCATIONDBOID := 42000000000000000000;
ELSE SELECT LOCATIONDBOID INTO V_LOCATIONDBOID FROM LOCATIONS WHERE LOCATIONID = TO_NUMBER(SUBSTR(V_EVENTDATADESC,1,3)) ;

would resolve this,

any ideas?