I *suspect* that reason for exceptions and solution are covered by 6609143.
(need to update NullFontScaler to return 1 as number of glyphs).
However, i can not reproduce this problem with your testcase on my windows using jdk7 (build both with freetype and t2k) and this problem is NOT fixed there.
It is possible that only freetype is failing on this font and t2k works with it.
But still, it should not be platform dependent and should fail on other platforms
using same font for both 6-open and 7. Ned further investigation.