1. Open "applicaton" example in creator. I think it could happen on any Qt example...
2. Switch to Debug page add breakpoint on "__cxa_throw" function.
3. Run debugging (F5)
4. get

   >~"breakpoint.c:6481: internal-error: expand_line_sal_maybe: Assertion `found' failed.\nA problem internal to GDB has been detected,\nfurther debugging may prove unreliable.\nQuit this debugging session? "
   >~"(y or n) [answered Y; input not from terminal]\n"
   >~"breakpoint.c:6481: internal-error: expand_line_sal_maybe: Assertion `found' failed.\nA problem internal to GDB has been detected,\nfurther debugging may prove unreliable.\nCreate a core file of GDB? "
   >~"(y or n) [answered Y; input not from terminal]\n"
   dUNEXPECTED GDB STDERR: 
   
   dThis application has requested the Runtime to terminate it in an unusual way.
   dPlease contact the application's support team for more information.
   
   d
   dGDB PROCESS FINISHED, status 0, code 255
   sПроцесс gdb неожиданно завершился (код 255).
   dPLAIN ADAPTER SHUTDOWN 10
   dState changed from InferiorRunning(10) to DebuggerNotReady(0).
   

Workaround is to use QtCreator 1.3.1. It works fine. And it have same gdb\gcc version. So I think it's not gdb problem!