I assume you are trying to make a wizard of some sort? I would suggest using one form with all your stuff in different frames, if you get what I mean. When the user clicks Next or Previous, you just show the apropriate form. This also gives you more control over what the user has input.

But if you must use multiple form, her another suggestion:
Call the forms from the main form, and make it have a return value which tells you which form to load next. Then loop this untill you get a certain return value, from that the user have pressed Cancel or Ok.

//Anders