Hi @Blaubart,
This suggests that you might not have enough RAM or you might have a CPU architecture problem. One problem that comes to mind is
... well, are you on a Raspberry Pi, and if so, which model?
Edit: By "a CPU architecture problem" I mean that some of your operating system packages might not actually be fully compatible with your CPU, for example because of the problem mentioned in the other thread where different Raspberry Pi devices have different kinds of ARM CPU and the apparently appropriate Debian packages in some cases are not compatible with the older devices.