You need to make sure both select queries are returning equal number of columns. As per comments, if you need to include extra columns, you can add static values to the other select query. So,
Adding (-1) as static values your CASE 1 would be like;
SELECT *, 1 AS fldBF,
ROW_NUMBER() OVER (PARTITION BY fldPK, fldCIA ORDER BY fldPK) AS sCount
INTO #tmpTable
FROM V_qryCSPGA
WHERE fldPK IN(SELECT DISTINCT thePK FROM FN_qryAllDTPK())
UNION ALL
SELECT *, -1 AS fldBF, -1 AS sCount --NOTE: Two static fields
FROM FN_qryCSGBA()
WHERE fldPK IN(SELECT DISTINCT thePK FROM FN_qryAllDTPK())
ORDER BY fldPK, fldCIA, fldNDat;
You could do the same thing to the second query.