cabinet_open{,_stream} function returns 0 on failure, which function passed to FDICreate.
Then, comments of FDICreate(in dlls/cabinet/fdi.c) says requirement of callbacks.
I quote the comment about open callback:
<quote>
 *   pfnopen  [I]  A pointer to a function which opens a file.  Uses
 *                 the same interface as _open.
</quote>

And MSDN documentation describes about _open, what should be compliant to.
http://msdn.microsoft.com/en-us/library/z0kc8e3z(v=vs.110).aspx

I also quote the Return Value section.
<quote>
Each of these functions returns a file descriptor for the opened file. A return value of -1 indicates an error, in which case errno is set to one of the following values.
</quote>

Therefore, cabinet_open{,_stream} should return -1 on failure.
I attached a my candidate patch, please check it.

Thanks,