As discussed in <a href="http://bugs.php.net/bug.php?id=54128">http://bugs.php.net/bug.php?id=54128</a> on Windows Server systems (2003, 2008) and IIS there is a problem when you want to unzip file stored in C:\Windows\Temp folder.User of worker process IUSR_XXX has no directory listing right for C:\Windows\Temp and this is a reason why ZipArchive::open() fails with error 11 (error open).