Debugging in D?

[Era Scarecrow]

  I'm using dmd v2.048, WinDbg 5.1. 

  I seem to be having trouble, perhaps i can get this cleared up. I'm trying to build a new structure type using math overloads (for testing). My asserts are failing; i need to debug them but can't. I've run 'dmd -gc mysource.d' as per the site, neither gdb nor windbg seems to want to accept it. When i use windbg supplied all i get is this:

> g _Dmain
Module Load: D:\PROGS\D\STR_BIGNUM.EXE  (symbol loading deferred)
Thread Create:  Process=0, Thread=0
Module Load: C:\WINDOWS\system32\NTDLL.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\KERNEL32.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\SHELL32.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\ADVAPI32.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\RPCRT4.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\SECUR32.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\GDI32.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\USER32.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\MSVCRT.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\SYSTEM32\SHLWAPI.DLL  (symbol loading deferred)
Module Load: C:\WINDOWS\system32\NTDLL.DLL  (no symbols loaded)
Module Load: D:\PROGS\D\STR_BIGNUM.EXE  (symbols loaded)
Module Load: C:\WINDOWS\WINSXS\X86_MICROSOFT.WINDOWS.COMMON-CONTROLS_6595B64144CCF1DF_6.0.2600.5512_X-WW_35D4CE83\COMCTL32.DLL
  (symbol loading deferred)
Module Load: C:\WINDOWS\WINSXS\X86_MICROSOFT.WINDOWS.COMMON-CONTROLS_6595B64144CCF1DF_6.0.2600.5512_X-WW_35D4CE83\COMCTL32.DLL
  (symbol loading deferred)
STR_BIGNUM!__Dmain+0x25:
0x004024c1  bed0404300       mov          esi,004340d0              
^C <process stopping...>
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