Hi, I also compiled mpqc-2.1.3 using export CC=gcc-3.2 export CXX=g++-3.2 export F77=g77-3.2 and encountered the same error. I got no info about line numbers either, but my guess is that the error happens at mpqc-2.1.3/src/lib/util/keyval/keyvalstr.cc on line 122: 121: DescribedClassProxy *proxy 122: = dynamic_cast<DescribedClassProxy*>(newdc.pointer()); 123: if (proxy) { As you see, there is a similar dynamic_cast statement that has caused the earlier problems as well. We still have the last dynamic_cast statement in qm1e_mpqc.cpp file, but the above error seems to happen before we reach it; this indeed explains why the breakpoint you set did not trigger. The problematic line is line 80, just a few lines above the set breakpoint: 80: if (keyval->exists("matrixkit")) 81: { 82: SCMatrixKit::set_default_matrixkit(dynamic_cast<>... About the background of this problem; when trying to compile the "ghemical" app using g++-3.2, it was found that the dynamic_cast<>() statements caused the program crash. I tried to make simple example programs, but those seemed to work fine. Also the heavily modified development version of the app had same symptoms, although the class structure is quite different. Removing the statements from "ghemical" seem to help but now it looks to that MPQC has similar behaviour with dynamic_cast and g++-3.2. I remember that about 4 months earlier, we were able to make .rpm packages for RedHat8 and Mandrake9, and those report using gcc-3.2 as well: $ g++ --version g++ (GCC) 3.2 20020903 (Red Hat Linux 8.0 3.2-7) Copyright (C) 2002 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ g++ --version g++ (GCC) 3.2 (Mandrake Linux 9.0 3.2-1mdk) Copyright (C) 2002 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Neither of the above machines are updated, just installed from rh8 and mdk9 CD's. I recompiled and tested: no dynamic_cast problems there! So is this either a new problem, or a Debian-related one? I have Debian "stable" and "testing" installations here, and both seem to have the problem with g++-3.2. I haven't tested g++3.1 or g++-3.0. Regards, Tommi