Here is the other picture, i circled the stem in the very back that looks like a ribbon.

The vine's stems are hollow......your plant stems are collapsing due to a lack of water up the vine.....this could be due to a borer or other injury to the stem.....
Take a look inside the stem before the dried out stems for borers....

I thought the same thing after doing some research online and so i took a clean razor blade and cut further up the stem from where the damage had ended and the healthy stem started up to about an inch and i found nothing so i tried to re-root it by burying the entire.damaged portion and a bit of the healthy portion of vine and the pumpkins all seemed to benifit because right after that they grew considerably, but now ive got one thats healthy and long and one thats got a really thick vine but the thick one wont grow much past 2 feet, its practically stopped growing at that length, do you think it will still be able to even hold a healthy pumpkin or is there too much damage done?

Time will tell.....keep tending it and keep soil moist...

PLEASE HELP. The leaves of my pumpkins, water melons and zucchini are dying. I have no idea what it is. There are caterpillar eggs on the pumpkin but no damage from them is evident.