Hi, one short answer:
((G9Q00002_1 < 2 && G9Q00002_2 <100) || (G9Q00002_3 < 7 && G9Q00002_4 < 12))
is not sufficient
You did not tell us, but you seem to use "multiple numeric" with subquestion codes 1,2,3,4.
Enter into question validation equation:
(!is_empty(G9Q00002_1) AND !is_empty(G9Q00002_2) AND G9Q00002_1<2 AND G9Q00002_2<100) OR (!is_empty(G9Q00002_3) AND !is_empty(G9Q00002_4) AND G9Q00002_3<7 AND G9Q00002_4<12)
Maybe better to use: array(numbers).
Then
(!is_empty(G9Q00002_SQ001_1) AND !is_empty(G9Q00002_SQ001_2) AND G9Q00002_SQ001_1<2 AND G9Q00002_SQ001_2<100) OR (!is_empty(G9Q00002_SQ002_1) AND !is_empty(G9Q00002_SQ002_2) AND G9Q00002_SQ002_1<7 AND G9Q00002_SQ002_2<12)
Joffm