Windows DVD Maker Telling Me That Edited VOB File Will Not Fit

Hi, I hope I am in the right forum for this question.

I have a problem that is baffling me and perhaps somebody may be able to explain my problem. Let me start at the beginning.

I had a bunch of VHS tapes of my family that I decided to have transferred on to DVDs. Now that they are on DVDs, I was hoping that I could use some software to split and edit parts that I choose from each DVD and put them on a new blank DVD and use Windows DVD Maker for the menus.
I had some success with a software called DVD Shr**k.

This is the funny thing. Once I put the whole DVD with the original VHS scenes in DVD Shr**k, they come out on
the computer as "VOB" files and Windows DVD Maker is allowing me to select the whole DVD with one of its menus. On some (not all), when I edit certain sections from that DVD and then put them in Windows DVD Maker, then I am being told that they will not fit. They are still backed up as "VOB" files and obviously smaller in size than the whole original DVD, (that Windows DVD Maker accepts and will burn to a blank DVD with menus) but the edited smaller versions or scenes will not fit on DVD Maker or so it is telling me.

Can anybody tell me why this is happening and how I get around this situation so that after I have edited the scenes from the original DVD, they will fit in Windows DVD Maker so that I can then use their excellent menus?
Is there something else I need to do so that it works?

Thanks in advance.

HB