>I made a backup copy of the old vcx and vct
>What happened was that a custom control suddenly became a formset control and lost all its proerties and methods.
>I think there is not anything to do...I tried but nothing.
>That what matters now is to understand what really happened.
What "really happened" is that you had no backup <g>.
A source control / version control system may also help to go back to a previous, valid, version of a form or other programming component.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)