FIRST QUESTION
Try this:
SELECT Indices.Month, Sum(IIf(Indices![SP 500 Index]>=0,1,0)) AS BullDJWA
FROM
(
SELECT Indices.Month, Sum(Abs(Bull_DJWA!BullDJWA-1)) AS BearDJWA
FROM Bull_DJWA
)
GROUP BY Indices.Month;
SECOND QUESTION
That's because you didn't join your tables in your query...