farkee,
Be sure to freeze the tomatoes individually first, as the liquid will get sucked up into the machine if you vacuum them fresh.
Also, there is a very helpful foodsavers group at yahoogroups with lots of good ideas and tips on how to use the machine. A company representative even is a member to help with difficulties. I would recommend checking it out. It has been extremely helpful to me.
FoodSaver@yahoogroups.com