I tried following and it is producing following errors.
X = DCount("*", "T_ProjAssigneeDetails", "ProjNum = '" & Me!CboSearchProj.Column(0) & " ' " And AssigneeActive Is Null) = False '")
Run-time error 424 - Object Required
X = DCount("*", "T_ProjAssigneeDetails", "ProjNum = '" & Me!CboSearchProj.Column(0) & " ' " And "AssigneeActive = 0")
Run-time error '13' - Type mismatch
X = DCount("*", "T_ProjAssigneeDetails", "ProjNum = '" & Me!CboSearchProj.Column(0) & " ' " And AssigneeActive Is Null) = False '")
Run-time error 424 - Object Required
X = DCount("*", "T_ProjAssigneeDetails", "ProjNum = '" & Me!CboSearchProj.Column(0) & " ' " And "AssigneeActive = 0")
Run-time error '13' - Type mismatch