When using ASCAN() the nStartElement and nElementsSearched parameters can not be empty if the nSearchColumn parameter is used. They must contain a -1.
ASCAN(aaray,"HELLO", , ,2,15) will return an error where ASCAN(aaray,"HELLO",-1,-1,2,15) will work.
ASCAN(aaray,"HELLO", , ,2,15) will return an error where ASCAN(aaray,"HELLO",-1,-1,2,15) will work.