Using a structure as shared memory

Hi:
Firstly, I apologise if thi is the wrong group, but I'm hoping someone can
help:
I am currently working on a project that needs to use a structure as a
shared memory block between processes. The structure is defined as follows:
struct SATreeviewInfo {

IAccessible* TreeviewAccessible;

VARIANT VarObject;

VARIANT VarObjectState;

HWND TreeviewWindow;

TV_ITEM CurrentItem;

LPWSTR Text[1024];

};

I have then declared a variable in a namespace (the structure is declared
inside this namespace also:

extern SATreeviewInfo TreeviewInfo;

The code for mapping this structure in to the process is as follows:

//Create the file mapping and event objects for treeviews.

HTreeviewMSAAMapFile =CreateFileMapping( INVALID_HANDLE_VALUE, NULL,
PAGE_READWRITE, 0, sizeof(SATreeviewInfo), TEXT("TreviewMapFile"));

The code tomap the structure is:

TreeviewInfo =(SATreeviewInfo)MapViewOfFile(HTreeviewMSAAMapFile, NULL, 0,
0, 0);

The error I obtain when trying to compile is:

1>c:\work\serotek\libserotek\treeview.cpp(26) : error C2440: 'type cast' :
cannot convert from 'LPVOID' to 'Treeview::SATreeviewInfo'

1> No constructor could take the source type, or constructor overload
resolution was ambiguous

Could someone tell me why the problem lies within this code, as I don't
think I am using a class--it's defined as a structure. What if any is the
fix.

Help gratefully apreciated.

Sean.