Hi -

It's probably because you have put square brackets around [Annual WTE salary].
Access cannot find this as a table field, so it thinks this is a parameter,
and asks for a value.  Try using Annual_WTE_salary, without the brackets.

John

Usually (not always, it works often enough to mislead you!) you cannot use a
calculated field in a further calculation; you will need to recapitulate the
expression used for [Annual WTE Salary] in the expression for the second
field, rather than referencing the calculated fieldname.

The problem is caused by you calculating Annual WTE Salary.  The expression
is not known for later calculations.  In some versions of Access you would
have to repeat the calculation every time it was used.  So your IIF
statements would be have to include the SUM calculation.

You might also check if you have applied and order by or filter criteria to
the query.  I might Copy the SQL into a new query and see if that got rid of
the request.

SELECT Sum([x confirmed].[hourly rate]*[wte]/7*365/12)
AS [Annual WTE salary]
, [x confirmed].name, staffs.practice, months.year, months.[ha year]
, staffs.[nhsp ees rate]
, IIf([nhsp ees rate]=0.05,0.05
  ,IIf([Annual WTE salary]>100000,0.085
  ,IIf([Annual WTE salary]>63417,0.075
  ,IIf([Annual WTE salary]>19165,0.065,0.05)))) AS Expr1
FROM months INNER JOIN (staffs INNER JOIN [x confirmed]
ON staffs.name = [x confirmed].name)
ON months.[month name] = [x confirmed].[month name]
WHERE ((([x confirmed].practice)=[Forms]![frm x main]![prac name]))
GROUP BY [x confirmed].name, staffs.practice, months.year, months.[ha year],
staffs.[nhsp ees rate], IIf([nhsp ees rate]=0.05,0.05,IIf([Annual WTE
salary]>100000,0.085,IIf([Annual WTE salary]>63417,0.075,IIf([Annual WTE
salary]>19165,0.065,0.05))))
HAVING (((months.year)=[Forms]![frm x main]![year]));