To reproduce:
1. Unzip the attached file to a directory. You will get main_.obj, qtdcore.lib and qtdgui.lib files.
2. Run dmd on those files:
dmd -gc main_.obj qtdcore.lib qtdgui.lib
The files were compiled with dmd 2.042 (BTW, there is no entry for that version in bugzilla).
The problem seems to be rooted in qtdgui.lib and shows up only if a large number of modules have been compiled into a single object file (200 in our case). qtdcore.lib is provided to avoid unresolved symbols.
See also http://d.puremagic.com/issues/show_bug.cgi?id=4009