This syntax "works", it just doesnt return anything
=IIf([AFSC]="2A5X1","N/A",DCount("*","1-Primary Table","[phaseonereq]=Yes and [phaseonecomp]=null and datediff('m', [arrivaldate], date())>=2 and datediff('m', [arrivaldate], date())<4 and [phaseonestatus]='UNQAL'"))