Read here about Windows Structured Storage:
http://msdn.microsoft.com/en-gb/library/windows/desktop/aa380020(v=vs.85).aspx
In particular, the name parameter:-
A pointer to a wide character null-terminated Unicode string that contains the name of the newly created stream. The name can be used later to open or reopen the stream. The name must not exceed 31 characters in length, not including the string terminator. The 000 through 01f characters, serving as the first character of the stream/storage name, are reserved for use by OLE. This is a compound file restriction, not a structured storage restriction.
So it's a reserved OLE name in some form. I don't know enough about structured storage to help you more, though.