Curious C++ segmentation fault

Can anyone suggest for me reasons why the first of these two fragments might produce a segmentation fault while the second works fine? ssc::RunSet has only one constructor, which takes no parameters. ++ #include"Executive.h" void ssc::Executive( int argc, const char* args[] ){ ... ssc::RunSet runset; /* FAILS HERE */ runset.run(); } ++ #include"Executive.h" void ssc::Executive( int argc, const char* args[] ){ ... ssc::RunSet* runset = new ssc::RunSet(); runset->run(); delete runset; } ++ -- JDL Non enim propter gloriam, diuicias aut honores pugnamus set propter libertatem solummodo quam Nemo bonus nisi simul cum vita amittit.