Maybe QT is a huge resource hogger when compiling.
I am using Debian and didn't have a swap file or partition and the compiler was dying even when I quit KDE and compiled without the overhead of a GUI. It was choking on Qtella.cpp, maybe because the constructor is 2000 lines long!! I am new to QT and C++ (been programming C for 15 years) and was amazed to see the compiled program is something like 13MB compared to say Gtk_Gnutella which is about 950k.