Version:           1.4.2 (using KDE KDE 3.4.3)
Installed from:    Ubuntu Packages
Compiler:          Target: i486-linux-gnu Linux (i686) release 2.6.12-9-386 (Ubuntu 5.10)
OS:                Linux

I have an file with four diagrams. One diagram is "classes componentes" and it has six classes: four with assoications and two that they are derived classes in this way:
class1 <>----> class2 <>-----> class3.
                ^<>-----> base
                          ^  ^
                          |  |---- derived1
                          |----- drived2
When I delete the base class in the Logical View tree, Umbrello crachs consistently.
When I delete derived1 and derived2 and, after, the base, the crachs don't ocourr