what is the data type of timerecorded field. if it is not number then change into val… if it is number change to cdbl(fieldname) … instead of putting total details in formula use only left side value one time and then check if it works fine that means the problem in second side field… also check whether your groups available with those names… in both ways you need to convert strings into numeric types… depening on backend information you have to use the fields. …