SELECT INTO must be the first query in a statement containing a UNION.
SELECT count(*) INTO :divModelTot1
FROM "table1"."info" i
WHERE i.compldate <:end
AND (i.agree is null OR i.agree>:start)
UNION ALL
SELECT count(*)
FROM "table2"."info" i
WHERE i.compldate <:end
AND (i.agree is null or i.agree>:start);