Hello Juan,
Could you look at bug 18786 and my suggested patch to get MINITAB working again. It is a partial revert of one of your patches from 6/25/08 (see comment #7).
I have verified that the associated tests (dlls/inetmib1/tests/main.c) exercise that code both pre and post revert. However the tests don't detect an error either way.
I know nothing about this code.
Thanks, Guy