Hi Rod,
Took the Is Null out like you said and did come up with a figure. So I have:
ContractA: DCount("[EmpKey]","tblEmployees","[StartDate]<#01/05/05#" & " AND [LeftDate] Is Null")
ContractB: DCount("[EmpKey]","tblEmployees","(([StartDate] >= #01/05/05#) AND ([StartDate] <=#31/12/05#)) AND...