You might need to double check your layout/record "context" here. Is this a calculation for a script step or a calculation field?
If you are setting up a calculation field, does the use of "calc::" mean that these values are from a related table? What have you selected in the "context" drop down at the top of the Specify Calculation dialog?
If this is for a script step, are you on a layout based on the "calc" table occurence? Or a layout based on a related table that has a valid link to the correct related record for the current record on your layout?