uVision3 hangs when downloading C++ executable

We bought an ADuC7020 QuickStart system.
GNU Compiler translates C++ programs successfully,
but uVision3 hangs when trying to download an executable file into the chip (through Keil ULINK).
Whereas C-programs download normally.

uVision3 hangs even when downloading such simplest program:

struct A
{
virtual void f()=0;
};
struct B : public A
{
virtual void f(){}
};
int main()
{
B b;
A* a = &b;
a->f();
return 0;
}

Thanks.

Dr. Tychinsky.