I've test with valgrind. No memory error found ^^

I check your build option and my visual project option. We have a difference .
You use /MT and i use /MD. In this config, on an xp the main example crash on the first unpack.
If i change you option to use /MD it don't crash :D
I found more information about this mix error here :
http://msdn.microsoft.com/en-us/library/2kzt1wy3(v=vs.71).aspx

Caution Do not mix static and dynamic versions of the run-time libraries. Having more than one copy of the run-time libraries in a process can cause problems, because static data in one copy is not shared with the other copy. The linker prevents you from linking with both static and dynamic versions within one .exe file, but you can still end up with two (or more) copies of the run-time libraries. For example, a dynamic-link library linked with the static (non-DLL) versions of the run-time libraries can cause problems when used with an .exe file that was linked with the dynamic (DLL) version of the run-time libraries. (You should also avoid mixing the debug and non-debug versions of the libraries in one process.)

I'll check tomorrow with my application if it's only that.

ps :I think you should propose a debug and a release dll with /MD and /MDd option.