The error message is telling you that the result of your calculation is a column / table. In most cases, the FILTER() function will be used with the CALCULATE() function, something like:
CALCULATE(SUM([sales]), FILTER(contact, contact[age] > 40))
The function above (assuming you have a sales column somewhere) will return the Sales for all contacts with age > 40. Depending on your purposes, you will need to replace SUM([sales]) with whatever you are trying to calculate.