Crash in Standard Zip Encryption Support resource

First, the background...

I posted about a crash bug I am having with encrypted zips in the Standard Zip Encryption Support resource: http://www.garagegames.com/index.php?sec=mg&mod=resource&page=view&qid=9896

To summarize what that post says, I am getting a crash in ZipLocalFileHeader::readFromStream(Stream &).

As an update to that post, the crash is happening specifically on the following line:

bool success = io_rStream.read(&m_header.headerSig);

The 'read' it is doing is somehow causing it to crash. Possibly the most strange part of all of this is that the issue seems to disappear when I try to debug the exact same executable. If I run the identical executable through XCode's debugger, the problem vanishes! I'm really not sure what to make of that and it is making the problem that much more difficult to fix. I was able to narrow the line down using 'print' statements, but I unfortunately cannot get any more information than that.

Does anyone have any ideas as to what might be causing this issue? For more information (including the crash log) see the previous post...

Thank you very much in advance for any help you might be able to offer.

Stephane