We do not have enough information to diagnose the problem on the tomatoes. The fruits and foliage of tomatoes can be subject to damage by many different diseases. Also, a large number of problems may be cultural and environmental. These include, insufficient water, nutrients, space, sunlight and support; poor soil, low pH, temperature extremes, root damage from cultivation, planting too late or early, plants not “hardened-off” properly, and setting out poor transplants.
Please see our online publication, "IPM Series: Tomatoes" http://hgic.umd.edu/_media/documents/hg56.pdf for more information on tomatoes and their diseases. Also, go to our Plant diagnostic Website and view photos of Spots/Rots on tomatoes http://plantdiagnostics.umd.edu/level2.cfm?categoryID=61
See our Photo Gallery of Tomato Diseases on Our Vegetable Website called "Grow It Eat It " http://growit.umd.edu/EarlyBlightPhotoGallery/