数える必要があるのは1つだけです。個々の要素が1でない場合はゼロなので、配列のサイズから1の数を引いて、ゼロの数を取得できます。
Function CountTheOnes(aArray As Variant) As Long
Dim x As Long
Dim OnesCount As Long
For x = LBound(aArray) To UBound(aArray)
If aArray(x) = 1 Then
OnesCount = OnesCount + 1
End If
Next
CountTheOnes = OnesCount
End Function
' and to test it:
Sub TestIt()
Dim aArray(1 To 10) As Byte
Dim x As Long
' stuff the array with zeros
For x = LBound(aArray) To UBound(aArray)
aArray(x) = 0
Next
' then add a couple of random 1s
aArray(3) = 1
aArray(7) = 1
aArray(9) = 1
x = CountTheOnes(aArray)
Debug.Print "Ones:" & vbTab & x
Debug.Print "Zeros:" & vbTab & UBound(aArray) - x
End Sub