I have no knowledge in this field and do not know how debug it.
I can compile my qt program(C++) in 32bit computer and work well. I also can compile it on 64bit computer, run and input some parameters, but it will exit when I push button to run and show this information.
Try compiling with debug symbols (Debug mode in Qt-Creator) and press the Debug button in the IDE.
If you're using a different ide than Qt creator you should compile with g++'s "-g" flag (eg: g++ -g source_1.cpp source_2.cpp -lQtCore -I/usr/include/QtCore etc...).
It is supposed to show you where the segmentation fault is happening.