Backtrace to be read

(gdb) backtrace
#0 0xffffe410 in __kernel_vsyscall ()
#1 0xb7218770 in raise () from /lib/tls/i686/cmov/libc.so.6
#2 0xb7219ef3 in abort () from /lib/tls/i686/cmov/libc.so.6
#3 0xb724dd0b in __fsetlocking () from /lib/tls/i686/cmov/libc.so.6
#4 0xb725742f in valloc () from /lib/tls/i686/cmov/libc.so.6
#5 0xb7257cdf in realloc () from /lib/tls/i686/cmov/libc.so.6
#6 0xb75280d4 in qRealloc (ptr=0x8132e58, size=56) at global/qglobal.cpp:1809
#7 0xb7547155 in QListData::realloc (this=0x8149874, alloc=9)
at tools/qlistdata.cpp:68
#8 0xb75473c7 in QListData::append (this=0x8149874) at tools/qlistdata.cpp:85
#9 0x0805c08d in QList<MTR::RowBox*>::append ()
#10 0x0805b5e4 in MTR::GameWidget::GameWidget ()
#11 0x0804f939 in MyWidget::CreateStackedWidgets ()
#12 0x08054d1b in MyWidget::MyWidget ()
#13 0x0804e27b in main ()

what does it mean?

It means your GameWidget constructor tried appending an item and reallocating the data in memory probably failed with a fatal error (libc called abort()).